Added inverter implementation

2024-01-05 16:27:39 +01:00
parent bd0bbd9c8b
commit 4586e72a0e
18 changed files with 1318 additions and 293 deletions
--- a/PLC/DUTs/ST_UNIT_HMI_INTERFACE.TcDUT
+++ b/PLC/DUTs/ST_UNIT_HMI_INTERFACE.TcDUT
@@ -26,11 +26,13 @@ STRUCT
 	// Drucksensoren Posolyt
 	//====================================
 	stPosolytPressureSegmentInlet : ST_HMI_ANALOG_VALUE;
+	stPosolytPressureTankInlet : ST_HMI_ANALOG_VALUE;

 	
 	// Drucksensoren Negolyt
 	//====================================
 	stNegolytPressureSegmentInlet : ST_HMI_ANALOG_VALUE;
+	stNegolytPressureTankInlet : ST_HMI_ANALOG_VALUE;
 	
 	
 	// Temperature sensor posolyt tank inlet
--- a/PLC/GVLs/GVL_CONFIG.TcGVL
+++ b/PLC/GVLs/GVL_CONFIG.TcGVL
@@ -44,69 +44,103 @@ VAR_GLOBAL
 		
 		// Pressure posolyt segment inlet
 		stConfigPosolytPressureSegmentInlet := (iAIMax := 32767, iAIMin := 0, rPVMax := 1500, rPVMin := -1000, sUnit := 'mbar'),
-		stEWLPosolytPressureSegmentInlet := (rErrorMin := -500, rWarningMin := -400, rWarningMax := 600, rErrorMax := 700),
+		stEWLPosolytPressureSegmentInlet := (rErrorMin := 170, rWarningMin := 200, rWarningMax := 600, rErrorMax := 700),
 		stEWDPosolytPressureSegmentInlet := 
 		(
 			timHardwareSignalLevelOn := T#0S,
 			timHardwareSignalLevelOff := T#5S,
-			timErrorLowOn := T#1S,
+			timErrorLowOn := T#2S,
 			timErrorLowOff := T#5S,
-			timWarningLowOn := T#1S,
+			timWarningLowOn := T#2S,
 			timWarningLowOff := T#5S,
-			timWarningHighOn := T#1S,
+			timWarningHighOn := T#2S,
 			timWarningHighOff := T#5S,
-			timErrorHighOn := T#1S,
+			timErrorHighOn := T#2S,
 			timErrorHighOff := T#5S
 		),
 		
 		// Pressure negolyt segment inlet
 		stConfigNegolytPressureSegmentInlet := (iAIMax := 32767, iAIMin := 0, rPVMax := 1500, rPVMin := -1000, sUnit := 'mbar'),
-		stEWLNegolytPressureSegmentInlet := (rErrorMin := -500, rWarningMin := -400, rWarningMax := 600, rErrorMax := 700),
+		stEWLNegolytPressureSegmentInlet := (rErrorMin := 170, rWarningMin := 200, rWarningMax := 600, rErrorMax := 700),
 		stEWDNegolytPressureSegmentInlet := 
 		(
 			timHardwareSignalLevelOn := T#0S,
 			timHardwareSignalLevelOff := T#5S,
-			timErrorLowOn := T#1S,
+			timErrorLowOn := T#2S,
 			timErrorLowOff := T#5S,
-			timWarningLowOn := T#1S,
+			timWarningLowOn := T#2S,
 			timWarningLowOff := T#5S,
-			timWarningHighOn := T#1S,
+			timWarningHighOn := T#2S,
 			timWarningHighOff := T#5S,
-			timErrorHighOn := T#1S,
+			timErrorHighOn := T#2S,
+			timErrorHighOff := T#5S
+		),
+		
+		// Pressure posolyt tank inlet
+		stConfigPosolytPressureTankInlet := (iAIMax := 32767, iAIMin := 0, rPVMax := 1500, rPVMin := -1000, sUnit := 'mbar'),
+		stEWLPosolytPressureTankInlet := (rErrorMin := -100, rWarningMin := -50, rWarningMax := 100, rErrorMax := 120),
+		stEWDPosolytPressureTankInlet := 
+		(
+			timHardwareSignalLevelOn := T#0S,
+			timHardwareSignalLevelOff := T#5S,
+			timErrorLowOn := T#2S,
+			timErrorLowOff := T#5S,
+			timWarningLowOn := T#2S,
+			timWarningLowOff := T#5S,
+			timWarningHighOn := T#2S,
+			timWarningHighOff := T#5S,
+			timErrorHighOn := T#2S,
+			timErrorHighOff := T#5S
+		),
+		
+		// Pressure negolyt tank inlet
+		stConfigNegolytPressureTankInlet := (iAIMax := 32767, iAIMin := 0, rPVMax := 1500, rPVMin := -1000, sUnit := 'mbar'),
+		stEWLNegolytPressureTankInlet := (rErrorMin := -100, rWarningMin := -50, rWarningMax := 100, rErrorMax := 120),
+		stEWDNegolytPressureTankInlet := 
+		(
+			timHardwareSignalLevelOn := T#0S,
+			timHardwareSignalLevelOff := T#5S,
+			timErrorLowOn := T#2S,
+			timErrorLowOff := T#5S,
+			timWarningLowOn := T#2S,
+			timWarningLowOff := T#5S,
+			timWarningHighOn := T#2S,
+			timWarningHighOff := T#5S,
+			timErrorHighOn := T#2S,
 			timErrorHighOff := T#5S
 		),
 		
 		// Temperature sensor posolyt tank inlet
 		stConfigPosolytTempTankInlet := (iAIMax := 32767, iAIMin := -32768, rPVMax := 3276.7, rPVMin := -3276.8, sUnit := '°C'),
-		stEWLPosolytTempTankInlet := (rErrorMin := -10, rWarningMin := -5, rWarningMax := 45, rErrorMax := 60),
+		stEWLPosolytTempTankInlet := (rErrorMin := -10, rWarningMin := -5, rWarningMax := 50, rErrorMax := 60),
 		stEWDPosolytTempTankInlet := 
 		(
 			timHardwareSignalLevelOn := T#0S,
 			timHardwareSignalLevelOff := T#5S,
-			timErrorLowOn := T#5S,
+			timErrorLowOn := T#2S,
 			timErrorLowOff := T#5S,
-			timWarningLowOn := T#5S,
+			timWarningLowOn := T#2S,
 			timWarningLowOff := T#5S,
-			timWarningHighOn := T#5S,
+			timWarningHighOn := T#2S,
 			timWarningHighOff := T#5S,
-			timErrorHighOn := T#5S,
+			timErrorHighOn := T#2S,
 			timErrorHighOff := T#5S
 		),
 		
 		// Temperature sensor negolyt tank inlet
 		stConfigNegolytTempTankInlet := (iAIMax := 32767, iAIMin := -32768, rPVMax := 3276.7, rPVMin := -3276.8, sUnit := '°C'),
-		stEWLNegolytTempTankInlet := (rErrorMin := -10, rWarningMin := -5, rWarningMax := 45, rErrorMax := 60),
+		stEWLNegolytTempTankInlet := (rErrorMin := -10, rWarningMin := -5, rWarningMax := 50, rErrorMax := 60),
 		stEWDNegolytTempTankInlet := 
 		(
 			timHardwareSignalLevelOn := T#0S,
 			timHardwareSignalLevelOff := T#5S,
-			timErrorLowOn := T#5S,
+			timErrorLowOn := T#2S,
 			timErrorLowOff := T#5S,
-			timWarningLowOn := T#5S,
+			timWarningLowOn := T#2S,
 			timWarningLowOff := T#5S,
-			timWarningHighOn := T#5S,
+			timWarningHighOn := T#2S,
 			timWarningHighOff := T#5S,
-			timErrorHighOn := T#5S,
+			timErrorHighOn := T#2S,
 			timErrorHighOff := T#5S
 		),
 		
@@ -115,7 +149,7 @@ VAR_GLOBAL
 		// Index 0x80n0:02 "Presentation" = Signed(0) -> Resolution 1/10°C
 		// Index 0x80n0:19 "RTD Element" = PT100(0)
 		stConfigVoltageSegment := (iAIMax := 32767, iAIMin := 0, rPVMax := 150, rPVMin := 0, sUnit := 'V'),
-		stEWLVoltageSegment := (rErrorMin := 50, rWarningMin := 55, rWarningMax := 75, rErrorMax := 80),
+		stEWLVoltageSegment := (rErrorMin := 50, rWarningMin := 55, rWarningMax := 75, rErrorMax := 79),
 		stEWDVoltageSegment := 
 		(
 			timHardwareSignalLevelOn := T#0S,
@@ -135,24 +169,51 @@ VAR_GLOBAL
 	// General settings
 	// ===========================
 	
-	// Pump on power
+	// Pump on power (%)
 	rPumpPosolytOnPower : REAL := 70.0;
 	rPumpNegolytOnPower : REAL := 70.0;
 	
-	// Unit voltage pumps shutoff threshold
-	rPumpshutoffThreshold : REAL := 25.0;
+	// Unit voltage pumps shutoff threshold (Volt)
+	rPumpshutoffThreshold : REAL := 15.0;
 	
-	// Minimum unit voltage for startup
+	// Minimum unit voltage required for inverter startup (Volt)
 	rMinimumUnitVoltage : REAL := 49.0;
 	
+	// Delta value to minimum unit voltage for shutdown discharge (Volt)
+	rDeltaUnitVoltageShutdownDischarge : REAL := 5.0;
+	
 	// Maximum absolute voltage difference
 	// between units in the same module
 	rMaxAbsDiffVoltageUnitsOnModule : REAL := 5.0;

 	// Maximum absolute voltage difference
-	// between Modules
+	// between Modules (Volt)
 	rMaxAbsDiffVoltageModulesInString : REAL := 10.0; 
 	
+	// Minimum absolute power command to enable battery (Watt)
+	diMinimumAbsPowerForEnable : DINT := 100;
+	
+	// Maximum allowed charging power (Watt)
+	diMaxStringChargingPower : DINT := -30_000;
+	
+	// Maximum allowed discharging power (Watt)
+	diMaxStringDischargePower : DINT := 30_000;
+	
+	// Inverter ip address
+	sInverterIp : STRING := '192.168.0.1';
+	
+	// Absolute shutdown discharge power (Watt)
+	rAbsShutdownDischargePower : REAL := 5_000;
+	
+	// Allow inverter fast shutdown discharge
+	xShutdownDischargeWithInverter : BOOL := TRUE;
+	
+	// String fully charged voltage (Volt)
+	rStringFullyChargedVoltage : REAL := 888.0;
+	
+	// String empty voltage (Volt)
+	rStringEmptyVoltage : REAL := 672.0;
+	
 END_VAR]]></Declaration>
  </GVL>
 </TcPlcObject>
--- a/PLC/GVLs/GVL_MODBUS.TcGVL
+++ b/PLC/GVLs/GVL_MODBUS.TcGVL
@@ -9,13 +9,15 @@ VAR_GLOBAL
 		sModelname := 'all liquid',
 		sSerialnumber := '202312151643',
 		sBMSVersion := '0.8.0',
-		uiTotalParallelMembers := 2);
+		uiTotalParallelMembers := 2,
+		eChargeStatus := E_CHARGE_STATUS.UNDEFINED,
+		eBatteryStatus := E_BATTERY_STATUS.OFF);
 	
 	// Modbus default config
-	mb_Input_Coils : ARRAY [0..255] OF BOOL;
-	mb_Output_Coils : ARRAY [0..255] OF BOOL;
-	mb_Input_Registers : ARRAY [0..255] OF WORD;
-	mb_Output_Registers : ARRAY [0..255] OF WORD;
+	//mb_Input_Coils : ARRAY [0..255] OF BOOL;
+	//mb_Output_Coils : ARRAY [0..255] OF BOOL;
+	//mb_Input_Registers : ARRAY [0..255] OF WORD;
+	//mb_Output_Registers : ARRAY [0..255] OF WORD;
 END_VAR]]></Declaration>
  </GVL>
 </TcPlcObject>
--- a/PLC/PLC.tmc
+++ b/PLC/PLC.tmc
--- a/PLC/POUs/FB_Module.TcPOU
+++ b/PLC/POUs/FB_Module.TcPOU
@@ -6,6 +6,12 @@ VAR_INPUT
 	// Emergency stop ok
 	xEmergencyStopOk : BOOL;
 	
+	// Enable
+	xEnable : BOOL;
+	
+	// Module completely off
+	xOff : BOOL := TRUE;
+	
 	// HMI Interface
 	stHMIInterface : REFERENCE TO ST_MODULE_HMI_INTERFACE;
 	
@@ -19,6 +25,18 @@ VAR_INPUT
 	xConfirmAlarms : BOOL;
 END_VAR
 VAR_OUTPUT
+	// Module voltage
+	rCurrentVoltage : REAL;	
+	
+	// Module ready
+	xReady : BOOL;
+	
+	// Module in shutdown segment discharge mode
+	xInShutdownDischargeMode : BOOL;
+	
+	// Module can be discharged during shutdown sequence
+	xShutdownDischargeAllowed : BOOL;
+
 	// One unit has an error
 	xError : BOOL;
 	
@@ -31,6 +49,12 @@ VAR
 	_fbUnit3 : FB_Unit(CONCAT(_sName, ' Unit 3'));
 	_fbUnit4 : FB_Unit(CONCAT(_sName, ' Unit 4'));
 	
+	// Flag for unit balance checking
+	_xBalanceOk : BOOL;
+	
+	// All units are ready
+	_xAllUnitsReady : BOOL;
+	
 	// Module name
 	_sName : STRING;
 END_VAR
@@ -44,6 +68,7 @@ xWarning := FALSE;
 // Unit 1
 // ===============================
 _fbUnit1(
+	xEnable := xEnable,
 	stUnitConfig:= GVL_CONFIG.stUnitConfig, 
 	stHMIInterface:= stHMIInterface.stHMIInterfaceUnit1, 
 	xEmergencyStopOk:= xEmergencyStopOk,  
@@ -67,6 +92,7 @@ END_IF
 // Unit 2
 // ===============================
 _fbUnit2(
+	xEnable := xEnable,
 	stUnitConfig:= GVL_CONFIG.stUnitConfig, 
 	stHMIInterface:= stHMIInterface.stHMIInterfaceUnit2, 
 	xEmergencyStopOk:= xEmergencyStopOk,  
@@ -90,6 +116,7 @@ END_IF
 // Unit 3
 // ===============================
 _fbUnit3(
+	xEnable := xEnable,
 	stUnitConfig:= GVL_CONFIG.stUnitConfig, 
 	stHMIInterface:= stHMIInterface.stHMIInterfaceUnit3, 
 	xEmergencyStopOk:= xEmergencyStopOk,  
@@ -113,6 +140,7 @@ END_IF
 // Unit 4
 // ===============================
 _fbUnit4(
+	xEnable := xEnable,
 	stUnitConfig:= GVL_CONFIG.stUnitConfig, 
 	stHMIInterface:= stHMIInterface.stHMIInterfaceUnit4, 
 	xEmergencyStopOk:= xEmergencyStopOk,  
@@ -129,6 +157,86 @@ END_IF

 IF _fbUnit4.xError THEN
 	xError := TRUE;
+END_IF
+
+
+// ===============================
+// Units ready check
+// ===============================
+_xAllUnitsReady := _fbUnit1.xReady AND _fbUnit2.xReady AND _fbUnit3.xReady AND _fbUnit4.xReady;
+
+
+// ===============================
+// Units in shutdown discharge mode
+// ===============================
+xInShutdownDischargeMode := _fbUnit1.xInShutdownDischargeMode AND _fbUnit2.xInShutdownDischargeMode AND _fbUnit3.xInShutdownDischargeMode AND _fbUnit4.xInShutdownDischargeMode;
+
+
+// ===============================
+// Units shutdown discharge allowed
+// ===============================
+xShutdownDischargeAllowed := _fbUnit1.xShutdownDischargeAllowed AND _fbUnit2.xShutdownDischargeAllowed AND _fbUnit3.xShutdownDischargeAllowed AND _fbUnit4.xShutdownDischargeAllowed;
+
+
+// ===============================
+// All units off
+// ===============================
+xOff := _fbUnit1.xOff AND _fbUnit2.xOff AND _fbUnit3.xOff AND _fbUnit4.xOff;
+
+// ===============================
+// Calculate module voltage
+// ===============================
+rCurrentVoltage := _fbUnit1.rCurrentVoltage + _fbUnit2.rCurrentVoltage + _fbUnit3.rCurrentVoltage + _fbUnit4.rCurrentVoltage;
+
+
+// ===============================
+// Module balance check
+// ===============================
+// Reset balance ok flag
+_xBalanceOk := TRUE;
+
+// Test unit 1 with unit 2
+IF ABS(_fbUnit1.rCurrentVoltage - _fbUnit2.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageUnitsOnModule THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test unit 1 with unit 3
+IF ABS(_fbUnit1.rCurrentVoltage - _fbUnit3.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageUnitsOnModule THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test unit 1 with unit 4
+IF ABS(_fbUnit1.rCurrentVoltage - _fbUnit4.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageUnitsOnModule THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test unit 2 with unit 3
+IF ABS(_fbUnit2.rCurrentVoltage - _fbUnit3.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageUnitsOnModule THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test unit 2 with unit 4
+IF ABS(_fbUnit2.rCurrentVoltage - _fbUnit4.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageUnitsOnModule THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test unit 3 with unit 4
+IF ABS(_fbUnit3.rCurrentVoltage - _fbUnit4.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageUnitsOnModule THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Signal an error if all units are ready and module is out of balance
+IF _xAllUnitsReady AND (NOT _xBalanceOk) THEN
+	xError := TRUE;
+END_IF
+
+// ===============================
+// Module ready validation check
+// ===============================
+IF _xAllUnitsReady AND _xBalanceOk THEN
+	xReady := TRUE;
+ELSE
+	xReady := FALSE;
 END_IF]]></ST>
    </Implementation>
    <Method Name="FB_init" Id="{369c1d27-76e4-45f8-9dbe-03524d3389df}">
@@ -145,8 +253,77 @@ END_VAR
      </Implementation>
    </Method>
    <LineIds Name="FB_Module">
-      <LineId Id="248" Count="92" />
+      <LineId Id="248" Count="7" />
+      <LineId Id="456" Count="0" />
+      <LineId Id="256" Count="22" />
+      <LineId Id="457" Count="0" />
+      <LineId Id="279" Count="22" />
+      <LineId Id="458" Count="0" />
+      <LineId Id="302" Count="22" />
+      <LineId Id="459" Count="0" />
+      <LineId Id="325" Count="15" />
      <LineId Id="188" Count="0" />
+      <LineId Id="441" Count="0" />
+      <LineId Id="436" Count="0" />
+      <LineId Id="438" Count="1" />
+      <LineId Id="437" Count="0" />
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+      <LineId Id="453" Count="1" />
+      <LineId Id="463" Count="0" />
+      <LineId Id="462" Count="0" />
+      <LineId Id="455" Count="0" />
    </LineIds>
    <LineIds Name="FB_Module.FB_init">
      <LineId Id="7" Count="0" />
--- a/PLC/POUs/FB_String.TcPOU
+++ b/PLC/POUs/FB_String.TcPOU
@@ -3,6 +3,9 @@
  <POU Name="FB_String" Id="{46501225-f446-4674-bfed-3be64273e576}" SpecialFunc="None">
    <Declaration><![CDATA[FUNCTION_BLOCK FB_String
 VAR_INPUT
+	// Enable
+	xEnable : BOOL;	
+
 	// Module 1 HMI interface
 	stHMIInterface : ST_STRING_HMI_INTERFACE;

@@ -19,6 +22,21 @@ VAR_INPUT
 	xConfirmAlarms : BOOL;
 END_VAR
 VAR_OUTPUT
+	// Current string voltage
+	rCurrentVoltage : REAL;
+	
+	// Module in shutdown segment discharge mode
+	xInShutdownDischargeMode : BOOL;
+	
+	// Module can be discharged during shutdown sequence
+	xShutdownDischargeAllowed : BOOL;
+
+	// String ready
+	xReady : BOOL;
+	
+	// String completely off
+	xOff : BOOL;
+	
 	xError : BOOL;
 	xWarning : BOOL;
 END_VAR
@@ -27,15 +45,28 @@ VAR
 	_fbModule2 : FB_Module(CONCAT(_sName, 'Module 2'));
 	_fbModule3 : FB_Module(CONCAT(_sName, 'Module 3'));
 	
+	// All modules are ready
+	_xAllModulesReady : BOOL;
+	
+	// All modules in shutdown discharge mode
+	_xAllModulesInShutdownDischargeMode : BOOL;
+	
+	// Flag for module balance checking
+	_xBalanceOk : BOOL;
+	
 	// String name
 	_sName : STRING;
 END_VAR
 ]]></Declaration>
    <Implementation>
-      <ST><![CDATA[// ===============================
+      <ST><![CDATA[// Reset error flag
+xError := FALSE;
+
+// ===============================
 // Module 1
 // ===============================
 _fbModule1(
+	xEnable := xEnable,
 	xEmergencyStopOk:= xEmergencyStopOk,
 	stHMIInterface:= stHMIInterface.stHMIInterfaceModule1, 
 	xReleaseErrors:= xReleaseErrors, 
@@ -55,6 +86,7 @@ END_IF
 // Module 2
 // ===============================
 _fbModule2(
+	xEnable := xEnable,
 	xEmergencyStopOk:= xEmergencyStopOk,
 	stHMIInterface:= stHMIInterface.stHMIInterfaceModule2, 
 	xReleaseErrors:= xReleaseErrors, 
@@ -74,6 +106,7 @@ END_IF
 // Module 3
 // ===============================
 _fbModule3(
+	xEnable := xEnable,
 	xEmergencyStopOk:= xEmergencyStopOk,
 	stHMIInterface:= stHMIInterface.stHMIInterfaceModule3, 
 	xReleaseErrors:= xReleaseErrors, 
@@ -86,6 +119,73 @@ END_IF

 IF _fbModule3.xError THEN
 	xError := TRUE;
+END_IF
+
+
+// ===============================
+// Modules ready check
+// ===============================
+_xAllModulesReady := _fbModule1.xReady AND _fbModule2.xReady AND _fbModule3.xReady;
+
+
+// ===============================
+// Modules in shutdown discharge mode
+// ===============================
+xInShutdownDischargeMode := _fbModule1.xInShutdownDischargeMode AND _fbModule2.xInShutdownDischargeMode AND _fbModule3.xInShutdownDischargeMode;
+
+
+// ===============================
+// Units shutdown discharge allowed
+// ===============================
+xShutdownDischargeAllowed := _fbModule1.xShutdownDischargeAllowed AND _fbModule2.xShutdownDischargeAllowed AND _fbModule3.xShutdownDischargeAllowed;
+
+
+// ===============================
+// All modules off
+// ===============================
+xOff := _fbModule1.xOff AND _fbModule2.xOff AND _fbModule3.xOff;
+
+
+// ===============================
+// Calculate module voltage
+// ===============================
+rCurrentVoltage := _fbModule1.rCurrentVoltage + _fbModule2.rCurrentVoltage + _fbModule3.rCurrentVoltage;
+
+
+// ===============================
+// String balance check
+// ===============================
+// Reset balance ok flag
+_xBalanceOk := TRUE;
+
+// Test module 1 with module 2
+IF ABS(_fbModule1.rCurrentVoltage - _fbModule2.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageModulesInString THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test module 1 with module 3
+IF ABS(_fbModule1.rCurrentVoltage - _fbModule3.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageModulesInString THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+// Test module 2 with module 3
+IF ABS(_fbModule2.rCurrentVoltage - _fbModule3.rCurrentVoltage) > GVL_CONFIG.rMaxAbsDiffVoltageModulesInString THEN
+	_xBalanceOk := FALSE;
+END_IF
+
+
+// Signal an error if all units are ready and module is out of balance
+IF _xAllModulesReady AND (NOT _xBalanceOk) THEN
+	xError := TRUE;
+END_IF
+
+// ===============================
+// String ready validation check
+// ===============================
+IF _xAllModulesReady AND _xBalanceOk THEN
+	xReady := TRUE;
+ELSE
+	xReady := FALSE;
 END_IF]]></ST>
    </Implementation>
    <Method Name="FB_init" Id="{9e8494eb-1b40-4be9-91c8-810ecbdf7f0c}">
@@ -102,9 +202,14 @@ END_VAR
      </Implementation>
    </Method>
    <LineIds Name="FB_String">
+      <LineId Id="266" Count="0" />
+      <LineId Id="268" Count="0" />
+      <LineId Id="267" Count="0" />
      <LineId Id="69" Count="0" />
      <LineId Id="67" Count="1" />
-      <LineId Id="47" Count="1" />
+      <LineId Id="47" Count="0" />
+      <LineId Id="140" Count="0" />
+      <LineId Id="48" Count="0" />
      <LineId Id="50" Count="3" />
      <LineId Id="58" Count="0" />
      <LineId Id="62" Count="0" />
@@ -112,10 +217,41 @@ END_VAR
      <LineId Id="66" Count="0" />
      <LineId Id="63" Count="0" />
      <LineId Id="59" Count="2" />
-      <LineId Id="71" Count="17" />
+      <LineId Id="71" Count="5" />
+      <LineId Id="141" Count="0" />
+      <LineId Id="77" Count="11" />
      <LineId Id="70" Count="0" />
-      <LineId Id="90" Count="17" />
+      <LineId Id="90" Count="5" />
+      <LineId Id="142" Count="0" />
+      <LineId Id="96" Count="11" />
      <LineId Id="89" Count="0" />
+      <LineId Id="183" Count="5" />
+      <LineId Id="245" Count="4" />
+      <LineId Id="244" Count="0" />
+      <LineId Id="261" Count="4" />
+      <LineId Id="260" Count="0" />
+      <LineId Id="270" Count="4" />
+      <LineId Id="269" Count="0" />
+      <LineId Id="197" Count="0" />
+      <LineId Id="190" Count="3" />
+      <LineId Id="182" Count="0" />
+      <LineId Id="199" Count="5" />
+      <LineId Id="198" Count="0" />
+      <LineId Id="209" Count="0" />
+      <LineId Id="208" Count="0" />
+      <LineId Id="230" Count="1" />
+      <LineId Id="211" Count="0" />
+      <LineId Id="232" Count="0" />
+      <LineId Id="210" Count="0" />
+      <LineId Id="234" Count="1" />
+      <LineId Id="233" Count="0" />
+      <LineId Id="213" Count="0" />
+      <LineId Id="212" Count="0" />
+      <LineId Id="237" Count="1" />
+      <LineId Id="236" Count="0" />
+      <LineId Id="215" Count="11" />
+      <LineId Id="239" Count="1" />
+      <LineId Id="214" Count="0" />
    </LineIds>
    <LineIds Name="FB_String.FB_init">
      <LineId Id="7" Count="0" />
--- a/PLC/POUs/FB_Unit.TcPOU
+++ b/PLC/POUs/FB_Unit.TcPOU
@@ -32,7 +32,16 @@ VAR_INPUT
 END_VAR
 VAR_OUTPUT
 	// Unit ready
-	xReady : BOOL;	
+	xReady : BOOL;
+	
+	// Unit completely off
+	xOff : BOOL := TRUE;
+	
+	// Unit can be discharged during shutdown sequence
+	xShutdownDischargeAllowed : BOOL;
+	
+	// Unit in shutdown segment discharge mode
+	xInShutdownDischargeMode : BOOL;

 	// Error active
 	xError : BOOL;
@@ -42,6 +51,9 @@ VAR_OUTPUT
 	
 	// Warning confirmation still pending
 	_xWarningConfirmPending : BOOL;
+	
+	// Current Unit voltage
+	rCurrentVoltage : REAL;
 END_VAR
 VAR
 	// Check unit condition after some time during startup
@@ -81,26 +93,26 @@ VAR
 	_stPosolytValveTankOutletPIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0000;
 	
 	_stPosolytValveTankOutletSIntlk : T_INTERLOCK;
-	_stPosolytValveTankOutletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0011;
+	_stPosolytValveTankOutletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0001;
 	
 	// Valve negolyt tank outlet interlocks
 	_stNegolytValveTankOutletPIntlk : T_INTERLOCK;
 	_stNegolytValveTankOutletPIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0000;
 	
 	_stNegolytValveTankOutletSIntlk : T_INTERLOCK;
-	_stNegolytValveTankOutletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0011;
+	_stNegolytValveTankOutletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0001;
 	
 	// Pump posolyt inlet interlocks
 	_stPosolytPumpInletPIntlk : T_INTERLOCK;
 	_stPosolytPumpInletPIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0001;
 	_stPosolytPumpInletSIntlk : T_INTERLOCK;
-	_stPosolytPumpInletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0011;
+	_stPosolytPumpInletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0001;
 	
 	// Pump negolyt inlet interlocks
 	_stNegolytPumpInletPIntlk : T_INTERLOCK;
 	_stNegolytPumpInletPIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0001;
 	_stNegolytPumpInletSIntlk : T_INTERLOCK;
-	_stNegolytPumpInletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0011;
+	_stNegolytPumpInletSIntlkUsed : T_INTERLOCK := 2#0000_0000_0000_0001;
 	
 	// Error active
 	_xErrorActive : BOOL;
@@ -108,6 +120,9 @@ VAR
 	// Warning active
 	_xWarningActive : BOOL;
 	
+	// Shutdown discharge allowed voltage
+	_rShutdownDischargeVoltageThreshold : REAL;
+	
 	// Current state
 	_iState: INT;
 	
@@ -122,6 +137,12 @@ VAR
 	
 	// Unit startup check timer
 	_tonStartupCheck : TON;
+	
+	// Enable voltage limit checks
+	_xEnableVoltageLimitChecks : BOOL;
+	
+	// Manual mode allowed flag
+	_xReleaseManualMode : BOOL;
 END_VAR
 ]]></Declaration>
    <Implementation>
@@ -141,7 +162,7 @@ _stPosolytValveTankOutletSIntlk.0 := xEmergencyStopOk;

 // Valve fb
 _fbPosolytValveTankOutlet(
-	xReleaseManualMode:= TRUE, 
+	xReleaseManualMode:= _xReleaseManualMode, 
 	wProcessINTLK:= _stPosolytValveTankOutletPIntlk, 
 	wProcessINTLKUsed:= _stPosolytValveTankOutletPIntlkUsed, 
 	wSafetyINTLK:= _stPosolytValveTankOutletSIntlk, 
@@ -167,7 +188,7 @@ _stNegolytValveTankOutletSIntlk.0 := xEmergencyStopOk;

 // Valve fb
 _fbNegolytValveTankOutlet(
-	xReleaseManualMode:= TRUE, 
+	xReleaseManualMode:= _xReleaseManualMode, 
 	wProcessINTLK:= _stNegolytValveTankOutletPIntlk, 
 	wProcessINTLKUsed:= _stNegolytValveTankOutletPIntlkUsed, 
 	wSafetyINTLK:= _stNegolytValveTankOutletSIntlk, 
@@ -198,7 +219,7 @@ _stPosolytPumpInletPIntlk.0 := _fbPosolytValveTankOutlet.IsOpen;
 	
 // Valve fb
 _fbPosolytPumpInlet(
-	xReleaseManualMode:= TRUE, 
+	xReleaseManualMode:= _xReleaseManualMode, 
 	wProcessINTLK:= _stPosolytPumpInletPIntlk, 
 	wProcessINTLKUsed:= _stPosolytPumpInletPIntlkUsed, 
 	wSafetyINTLK:= _stPosolytPumpInletSIntlk, 
@@ -237,7 +258,7 @@ _stNegolytPumpInletPIntlk.0 := _fbNegolytValveTankOutlet.IsOpen;
 	
 // Valve fb
 _fbNegolytPumpInlet(
-	xReleaseManualMode:= TRUE, 
+	xReleaseManualMode:= _xReleaseManualMode, 
 	wProcessINTLK:= _stNegolytPumpInletPIntlk, 
 	wProcessINTLKUsed:= _stNegolytPumpInletPIntlkUsed, 
 	wSafetyINTLK:= _stNegolytPumpInletSIntlk, 
@@ -262,14 +283,14 @@ END_IF


 // ===============================
-// Pressure sensors posolyt segment inlet
+// Pressure sensor posolyt segment inlet
 // ===============================
 _fbPressurePosolytSegmentInlet(
 	stScalingConfig:= stUnitConfig.stConfigPosolytPressureSegmentInlet, 
 	stEWConfig:= stUnitConfig.stEWLPosolytPressureSegmentInlet, 
 	stEWDelayConfig:= stUnitConfig.stEWDPosolytPressureSegmentInlet, 
 	xReleaseErrors:= xReleaseErrors, 
-	xReleaseLimitErrors:= xReleaseLimitErrors, 
+	xReleaseLimitErrors:= xReleaseLimitErrors AND _fbPosolytPumpInlet.IsRunning AND _fbPosolytPumpInlet.xInTarget, 
 	xReleaseHardwareErrors:= xReleaseErrors, 
 	xConfirmAlarms:= xConfirmAlarms,
 	stHMIInterface => stHMIInterface.stPosolytPressureSegmentInlet);
@@ -293,7 +314,7 @@ _fbPressureNegolytSegmentInlet(
 	stEWConfig:= stUnitConfig.stEWLNegolytPressureSegmentInlet, 
 	stEWDelayConfig:= stUnitConfig.stEWDNegolytPressureSegmentInlet, 
 	xReleaseErrors:= xReleaseErrors, 
-	xReleaseLimitErrors:= xReleaseLimitErrors, 
+	xReleaseLimitErrors:= xReleaseLimitErrors AND _fbNegolytPumpInlet.IsRunning AND _fbNegolytPumpInlet.xInTarget, 
 	xReleaseHardwareErrors:= xReleaseErrors, 
 	xConfirmAlarms:= xConfirmAlarms,
 	stHMIInterface => stHMIInterface.stNegolytPressureSegmentInlet);
@@ -310,17 +331,107 @@ END_IF


 // ===============================
-// Voltage segment
+// Pressure sensors posolyt tank inlet
 // ===============================
-_fbVoltageSegment(
-	stScalingConfig:= , 
-	stEWConfig:= , 
-	stEWDelayConfig:= , 
+_fbPressurePosolytTankInlet(
+	stScalingConfig:= stUnitConfig.stConfigPosolytPressureTankInlet, 
+	stEWConfig:= stUnitConfig.stEWLPosolytPressureTankInlet, 
+	stEWDelayConfig:= stUnitConfig.stEWDPosolytPressureTankInlet, 
+	xReleaseErrors:= xReleaseErrors, 
+	xReleaseLimitErrors:= xReleaseLimitErrors AND _fbPosolytPumpInlet.IsRunning AND _fbPosolytPumpInlet.xInTarget, 
+	xReleaseHardwareErrors:= xReleaseErrors, 
+	xConfirmAlarms:= xConfirmAlarms,
+	stHMIInterface => stHMIInterface.stPosolytPressureTankInlet);
+	
+// Set error active if fb has error
+IF _fbPressurePosolytTankInlet.xError THEN
+	_xErrorActive := TRUE;
+END_IF
+
+// Set warning if fb has warning
+IF _fbPressurePosolytTankInlet.xWarning THEN
+	_xWarningActive := TRUE;
+END_IF
+
+
+// ===============================
+// Pressure sensors negolyt tank inlet
+// ===============================
+_fbPressureNegolytTankInlet(
+	stScalingConfig:= stUnitConfig.stConfigNegolytPressureTankInlet, 
+	stEWConfig:= stUnitConfig.stEWLNegolytPressureTankInlet, 
+	stEWDelayConfig:= stUnitConfig.stEWDNegolytPressureTankInlet, 
+	xReleaseErrors:= xReleaseErrors, 
+	xReleaseLimitErrors:= xReleaseLimitErrors AND _fbNegolytPumpInlet.IsRunning AND _fbNegolytPumpInlet.xInTarget, 
+	xReleaseHardwareErrors:= xReleaseErrors, 
+	xConfirmAlarms:= xConfirmAlarms,
+	stHMIInterface => stHMIInterface.stNegolytPressureTankInlet);
+	
+// Set error active if fb has error
+IF _fbPressureNegolytTankInlet.xError THEN
+	_xErrorActive := TRUE;
+END_IF
+
+// Set warning if fb has warning
+IF _fbPressureNegolytTankInlet.xWarning THEN
+	_xWarningActive := TRUE;
+END_IF
+
+// ===============================
+// Temperature sensor posolyt tank inlet
+// ===============================
+_fbTempSensorPosolyt(
+	stScalingConfig:= stUnitConfig.stConfigPosolytTempTankInlet, 
+	stEWConfig:= GVL_CONFIG.stUnitConfig.stEWLPosolytTempTankInlet, 
+	stEWDelayConfig:= GVL_CONFIG.stUnitConfig.stEWDPosolytTempTankInlet,  
 	xReleaseErrors:= xReleaseErrors, 
 	xReleaseLimitErrors:= xReleaseLimitErrors, 
 	xReleaseHardwareErrors:= xReleaseErrors, 
 	xConfirmAlarms:= xConfirmAlarms, 
-	stHMIInterface=> stHMIInterface.stVoltageSegment);
+	stHMIInterface=> stHMIInterface.stPosolytTempTankInlet);
+	
+IF _fbTempSensorPosolyt.xError THEN
+	_xErrorActive := TRUE;
+END_IF
+
+IF _fbTempSensorPosolyt.xWarning THEN
+	_xWarningActive := TRUE;
+END_IF
+
+// ===============================
+// Temperature sensor negolyt tank inlet
+// ===============================
+_fbTempSensorNegolyt(
+	stScalingConfig:= stUnitConfig.stConfigNegolytTempTankInlet, 
+	stEWConfig:= GVL_CONFIG.stUnitConfig.stEWLNegolytTempTankInlet, 
+	stEWDelayConfig:= GVL_CONFIG.stUnitConfig.stEWDNegolytTempTankInlet,  
+	xReleaseErrors:= xReleaseErrors, 
+	xReleaseLimitErrors:= xReleaseLimitErrors, 
+	xReleaseHardwareErrors:= xReleaseErrors, 
+	xConfirmAlarms:= xConfirmAlarms, 
+	stHMIInterface=> stHMIInterface.stNegolytTempTankInlet);
+	
+IF _fbTempSensorNegolyt.xError THEN
+	_xErrorActive := TRUE;
+END_IF
+
+IF _fbTempSensorNegolyt.xWarning THEN
+	_xWarningActive := TRUE;
+END_IF
+
+// ===============================
+// Voltage segment
+// ===============================
+_fbVoltageSegment(
+	stScalingConfig:= GVL_CONFIG.stUnitConfig.stConfigVoltageSegment, 
+	stEWConfig:= GVL_CONFIG.stUnitConfig.stEWLVoltageSegment, 
+	stEWDelayConfig:= GVL_CONFIG.stUnitConfig.stEWDVoltageSegment, 
+	xReleaseErrors:= xReleaseErrors, 
+	xReleaseLimitErrors:= xReleaseLimitErrors AND _xEnableVoltageLimitChecks, 
+	xReleaseHardwareErrors:= xReleaseErrors, 
+	xConfirmAlarms:= xConfirmAlarms, 
+	stHMIInterface=> stHMIInterface.stVoltageSegment,
+	rScaledValue => rCurrentVoltage);
 	
 // Set error active if fb has error
 IF _fbVoltageSegment.xError THEN
@@ -351,30 +462,36 @@ IF _fbNotAllAutomaticAlarm.bRaised AND _xAllComponentsInAutomatic THEN
 	_fbNotAllAutomaticAlarm.Clear(0, TRUE);
 END_IF

+// Calculate shutdown discharge threshold
+_rShutdownDischargeVoltageThreshold := GVL_CONFIG.rMinimumUnitVoltage + GVL_CONFIG.rDeltaUnitVoltageShutdownDischarge;
+
 // ===============================
 // Run state machine for startup and shutdown
 // ===============================
 CASE _iState OF
 	0: // Off
 		IF xEnable AND _xAllComponentsInAutomatic AND (NOT _xErrorActive) THEN
+			_xReleaseManualMode := FALSE;
 			_iState := 10;
 		END_IF
 	
 	10: // Open all valves
 		_fbPosolytValveTankOutlet.ReqAutomaticOpen();
 		_fbNegolytValveTankOutlet.ReqAutomaticOpen();
+		xOff := FALSE;
 		_iState := 15;
 		
 	15: // Wait for all valves to be open
 		IF _fbPosolytValveTankOutlet.IsOpen AND _fbNegolytValveTankOutlet.IsOpen THEN
-			IF NOT _fbPosolytValveTankOutlet.xError AND _fbNegolytValveTankOutlet.xError THEN
+			IF (NOT _fbPosolytValveTankOutlet.xError) AND (NOT _fbNegolytValveTankOutlet.xError) THEN
 				_iState := 20;
 			END_IF
 		END_IF
 		
 		// If enable signal is lost, or there is an error, goto shutdown
 		IF (NOT xEnable) OR _xErrorActive THEN
-			_iState := 40;
+			_xReleaseManualMode := TRUE;
+			_iState := 1000;
 		END_IF
 	
 	20: // Start pumps
@@ -397,11 +514,13 @@ CASE _iState OF
 		
 		// After some time, check if all values are ok
 		IF _tonStartupCheck.Q THEN
+			_tonStartupCheck(In := FALSE);
 			// Check for minimum unit voltage
-			IF _fbVoltageSegment.rScaledValue >= GVL_CONFIG.rMinimumUnitVoltage AND
-					NOT _xErrorActive AND
-					NOT _xWarningActive THEN
+			IF (_fbVoltageSegment.rScaledValue >= GVL_CONFIG.rMinimumUnitVoltage)
+					AND NOT _xErrorActive
+					AND NOT _xWarningActive THEN
 				xReady := TRUE;
+				_xEnableVoltageLimitChecks := TRUE;
 				_iState := 35;
 			ELSE
 				_iState := 40;
@@ -414,9 +533,15 @@ CASE _iState OF
 		END_IF
 		
 	35: // Unit in enabled state
-		IF (NOT xEnable) OR _xErrorActive THEN
+		IF (NOT xEnable) AND NOT _xErrorActive THEN
+			_xEnableVoltageLimitChecks := FALSE;
 			_iState := 40;
 		END_IF
+		
+		// Goto error shutdown if an error occured
+		IF _xErrorActive THEN
+			_iState := 1000;
+		END_IF
 	
 	40: // Close all valves
 		_fbNegolytValveTankOutlet.ReqAutomaticClose();
@@ -425,6 +550,7 @@ CASE _iState OF
 		
 	45: // Wait for valves to be closed
 		IF _fbNegolytValveTankOutlet.IsClosed AND _fbPosolytValveTankOutlet.IsClosed THEN
+			xInShutdownDischargeMode := TRUE;
 			_iState := 50;
 		END_IF
 		
@@ -440,12 +566,22 @@ CASE _iState OF
 		END_IF
 	
 	50: // Wait for unit voltage to drop below a certain threshold
+		IF (_fbVoltageSegment.rScaledValue > _rShutdownDischargeVoltageThreshold) THEN
+			xShutdownDischargeAllowed := TRUE;
+		ELSE
+			xShutdownDischargeAllowed := FALSE;
+		END_IF
+		
 		IF (_fbVoltageSegment.rScaledValue <= GVL_CONFIG.rPumpshutoffThreshold) THEN
+			xShutdownDischargeAllowed := FALSE;
+			xInShutdownDischargeMode := FALSE;
 			_iState := 60;
 		END_IF
 		
 		// Check for restart condition
 		IF xEnable AND (NOT _xErrorActive) THEN
+			xShutdownDischargeAllowed := FALSE;
+			xInShutdownDischargeMode := FALSE;
 			_iState := 0;
 		END_IF
 		
@@ -456,10 +592,10 @@ CASE _iState OF
 		
 	65: // Wait for pumps to be stopped
 		IF _fbPosolytPumpInlet.IsStopped AND _fbNegolytPumpInlet.IsStopped THEN
-			IF _xErrorActive THEN
+			xOff := TRUE;
+			_xReleaseManualMode := TRUE;
+			IF NOT _xErrorActive THEN
 				_iState := 1000;
-			ELSE
-				_iState := 0;
 			END_IF
 		END_IF
 		
@@ -467,8 +603,25 @@ CASE _iState OF
 		IF xEnable AND (NOT _xErrorActive) THEN
 			_iState := 0;
 		END_IF
+		
+		// Check for error
+		IF _xErrorActive THEN
+			_iState := 1000;
+		END_IF
 	
-	1000: // Alarm active
+	1000: // Error shutdown
+		_fbNegolytValveTankOutlet.ReqAutomaticClose();
+		_fbPosolytValveTankOutlet.ReqAutomaticClose();
+		_fbPosolytPumpInlet.ReqAutomaticStop();
+		_fbNegolytPumpInlet.ReqAutomaticStop();
+		_xEnableVoltageLimitChecks := FALSE;
+		xShutdownDischargeAllowed := FALSE;
+		xInShutdownDischargeMode := FALSE;
+		xReady := FALSE;
+		xOff := TRUE;
+		_iState := 1001;
+		
+	1001: // Alarm active
 		// Only allow reset when enable is deactivated to avoid an
 		// automatic restart of the unit
 		IF (NOT _xErrorActive) AND (NOT xEnable) THEN
@@ -505,29 +658,107 @@ _fbNotAllAutomaticAlarm.ipArguments.Clear().AddString(_sName);]]></ST>
      <LineId Id="4263" Count="102" />
      <LineId Id="4619" Count="0" />
      <LineId Id="4367" Count="46" />
-      <LineId Id="4621" Count="22" />
+      <LineId Id="5099" Count="0" />
+      <LineId Id="5101" Count="2" />
+      <LineId Id="5095" Count="0" />
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+      <LineId Id="5104" Count="1" />
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-      <LineId Id="4444" Count="26" />
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-      <LineId Id="4511" Count="17" />
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      <LineId Id="4653" Count="0" />
      <LineId Id="4655" Count="2" />
      <LineId Id="4654" Count="0" />
-      <LineId Id="4529" Count="4" />
+      <LineId Id="4529" Count="1" />
+      <LineId Id="5220" Count="0" />
+      <LineId Id="5223" Count="0" />
+      <LineId Id="5225" Count="1" />
+      <LineId Id="5224" Count="0" />
+      <LineId Id="5221" Count="0" />
+      <LineId Id="4531" Count="0" />
+      <LineId Id="5228" Count="0" />
+      <LineId Id="5242" Count="0" />
+      <LineId Id="4532" Count="1" />
      <LineId Id="4658" Count="0" />
-      <LineId Id="4660" Count="2" />
+      <LineId Id="4660" Count="1" />
+      <LineId Id="5229" Count="0" />
+      <LineId Id="5243" Count="0" />
+      <LineId Id="4662" Count="0" />
      <LineId Id="4659" Count="0" />
      <LineId Id="4569" Count="0" />
-      <LineId Id="4535" Count="12" />
+      <LineId Id="4535" Count="6" />
+      <LineId Id="5251" Count="0" />
+      <LineId Id="4944" Count="0" />
+      <LineId Id="4542" Count="1" />
+      <LineId Id="4546" Count="1" />
      <LineId Id="4663" Count="0" />
      <LineId Id="4665" Count="2" />
      <LineId Id="4664" Count="0" />
-      <LineId Id="4548" Count="6" />
+      <LineId Id="5252" Count="4" />
+      <LineId Id="4548" Count="0" />
+      <LineId Id="5084" Count="0" />
+      <LineId Id="5086" Count="1" />
+      <LineId Id="5089" Count="1" />
+      <LineId Id="5093" Count="0" />
+      <LineId Id="5227" Count="0" />
+      <LineId Id="5240" Count="0" />
+      <LineId Id="5092" Count="0" />
+      <LineId Id="5258" Count="0" />
+      <LineId Id="5091" Count="0" />
+      <LineId Id="5085" Count="0" />
+      <LineId Id="4549" Count="5" />
      <LineId Id="4556" Count="6" />
      <LineId Id="2754" Count="0" />
    </LineIds>
--- a/PLC/POUs/MAIN.TcPOU
+++ b/PLC/POUs/MAIN.TcPOU
@@ -4,25 +4,325 @@
    <Declaration><![CDATA[PROGRAM MAIN
 VAR
 	_xEmergencyStopOk AT %I* : BOOL;
-	_xReleaseErrors : BOOL;
-	_xReleaseLimitsErrors : BOOL;
+	_xReleaseErrors : BOOL := TRUE;
+	_xReleaseLimitsErrors : BOOL := TRUE;
 	_xConfirmAlarms : BOOL;
+	_xEnableString : BOOL;
+	_xEnableInverter : BOOL;
 	_fbString : FB_String('String 1');
+	_fbInverter : FB_PowerSupplySunspec;
+	
+	_iState : INT;
+	
+	// Internal inverter power
+	_rPowerInverter : REAL;
+	
+	// Flag for zero power indication
+	_xNoPowerRequested : BOOL;
+	
+	// Startup delay for error release during plc startup
+	_tonStartupDelay : TON := (PT := T#10S);
+	
+	// Small delay for inverter shutdown
+	_tonBeginShutdown : TON := (PT := T#10S);
 END_VAR
 ]]></Declaration>
    <Implementation>
-      <ST><![CDATA[_fbString(
+      <ST><![CDATA[// Dely release of errors during PLC startup phase
+_tonStartupDelay(IN := TRUE);
+
+// Call string 1
+_fbString(
+	xEnable := _xEnableString,
 	stHMIInterface:= , 
 	xEmergencyStopOk:= _xEmergencyStopOk, 
-	xReleaseErrors:= _xReleaseErrors, 
-	xReleaseLimitErrors:= _xReleaseLimitsErrors, 
-	xConfirmAlarms:= _xConfirmAlarms, 
-	xError=> , 
-	xWarning=> );]]></ST>
+	xReleaseErrors:= _xReleaseErrors AND _tonStartupDelay.Q, 
+	xReleaseLimitErrors:= _xReleaseLimitsErrors AND _tonStartupDelay.Q, 
+	xConfirmAlarms:= _xConfirmAlarms);
+	
+	
+// Call inverter
+//_fbInverter(
+//	sInverterIPAddr:= GVL_CONFIG.sInverterIp, 
+//	xEnable:= _xEnableInverter, 
+//	rPower:= _rPowerInverter, 
+//	xReset:= _xConfirmAlarms, 
+//	rMaxBattPower:= DINT_TO_REAL(GVL_CONFIG.diMaxStringDischargePower), 
+//	xCloseDCRelais=> , 
+//	rActDCCurrent=> , 
+//	rActDCVoltage=> , 
+//	xError=> , 
+//	xActive=> );
+	
+
+// ===============================
+// State machine
+// ===============================
+CASE _iState OF
+	0: // Idle
+		// Wait for power command
+		IF ABS(GVL_MODBUS.stModbusEMSComm.diSetpointActivePower) > GVL_CONFIG.diMinimumAbsPowerForEnable THEN
+			_iState := 5;
+		END_IF
+		
+	5: // Check if power command is within limits
+		IF GVL_MODBUS.stModbusEMSComm.diSetpointActivePower < GVL_CONFIG.diMaxStringDischargePower
+				AND GVL_MODBUS.stModbusEMSComm.diSetpointActivePower > GVL_CONFIG.diMaxStringChargingPower THEN
+			_xEnableString := TRUE;
+			_iState := 10;
+		ELSE
+			// Set error bitmap flag
+			GVL_MODBUS.stModbusEMSComm.lwErrorBitmap.0 := 1;
+			
+			// Goto error state
+			_iState := 1000;
+		END_IF
+		
+	10: // Wait for string to be ready
+		IF _fbString.xReady AND (NOT _fbString.xError) THEN
+			_iState := 20;
+		END_IF
+		
+	20: // Start main inverter with zero power
+		_rPowerInverter := 0.0;
+		_xEnableInverter := TRUE;
+		_iState := 25;
+	
+	25: // Wait for inverter to be ready
+		IF _fbInverter.xActive AND (NOT _fbInverter.xError) THEN
+			GVL_MODBUS.stModbusEMSComm.eBatteryStatus := E_BATTERY_STATUS.ACTIVE;
+			_iState := 30;
+		END_IF
+		
+		// Check for errors
+		IF _fbString.xError OR _fbInverter.xError THEN
+			_iState := 1000;
+		END_IF
+		
+	30: // String and inverter enabled
+		// Set inverter power to modbus requested power
+		_rPowerInverter := DINT_TO_REAL(GVL_MODBUS.stModbusEMSComm.diSetpointActivePower);
+		
+		// Check if the battery should still be active
+		IF (GVL_MODBUS.stModbusEMSComm.diSetpointActivePower = 0) THEN
+			_xNoPowerRequested := TRUE;
+		ELSE
+			_xNoPowerRequested := FALSE;
+		END_IF
+		
+		// Set battery status
+		IF GVL_MODBUS.stModbusEMSComm.diSetpointActivePower > 0 THEN
+			GVL_MODBUS.stModbusEMSComm.eChargeStatus := E_CHARGE_STATUS.DISCHARGING;
+		ELSIF GVL_MODBUS.stModbusEMSComm.diSetpointActivePower < 0 THEN
+			GVL_MODBUS.stModbusEMSComm.eChargeStatus := E_CHARGE_STATUS.CHARGING;
+		ELSE
+			GVL_MODBUS.stModbusEMSComm.eChargeStatus := E_CHARGE_STATUS.UNDEFINED;
+		END_IF
+		
+		// Add small delay before shutdown by EMS is detected
+		_tonBeginShutdown(IN := _xNoPowerRequested);
+		
+		// shutdown triggered from EMS
+		IF _tonBeginShutdown.Q THEN
+			_tonBeginShutdown(In := FALSE);
+			
+			// Set inverter to zero power
+			_rPowerInverter := 0.0;
+			
+			// Start string shutdown
+			_xEnableString := FALSE;
+			_iState := 35;
+		END_IF
+		
+		// Shutdown triggered by battery fully charged
+		IF GVL_MODBUS.stModbusEMSComm.eChargeStatus = E_CHARGE_STATUS.CHARGING AND (_fbString.rCurrentVoltage >= GVL_CONFIG.rStringFullyChargedVoltage) THEN
+			_tonBeginShutdown(In := FALSE);
+			
+			// Set inverter to zero power
+			_rPowerInverter := 0.0;
+			
+			// Start string shutdown
+			_xEnableString := FALSE;
+			
+			// Change battery status
+			GVL_MODBUS.stModbusEMSComm.eChargeStatus := E_CHARGE_STATUS.FULL;
+			
+			_iState := 35;
+		END_IF
+		
+		// Shutdown triggered by battery empty
+		IF GVL_MODBUS.stModbusEMSComm.eChargeStatus = E_CHARGE_STATUS.DISCHARGING AND (_fbString.rCurrentVoltage <= GVL_CONFIG.rStringEmptyVoltage) THEN
+			_tonBeginShutdown(In := FALSE);
+			
+			// Set inverter to zero power
+			_rPowerInverter := 0.0;
+			
+			// Start string shutdown
+			_xEnableString := FALSE;
+			
+			// Change battery status
+			GVL_MODBUS.stModbusEMSComm.eChargeStatus := E_CHARGE_STATUS.FULL;
+			
+			_iState := 35;
+		END_IF
+		
+		// Check for errors
+		IF _fbString.xError OR _fbInverter.xError THEN
+			_tonBeginShutdown(In := FALSE);
+			_iState := 1000;
+		END_IF
+		
+	35: // Wait for string to be in shutdown discharge mode
+		IF _fbString.xInShutdownDischargeMode THEN
+			// Check if we are allowed to discharge during shutdown with inverter
+			IF GVL_CONFIG.xShutdownDischargeWithInverter THEN
+				_iState := 40;
+			ELSE
+				_rPowerInverter := 0.0;
+				_xEnableInverter := FALSE;
+				_iState := 45;
+			END_IF
+		END_IF
+		
+		// Check for errors
+		IF _fbString.xError OR _fbInverter.xError THEN
+			_iState := 1000;
+		END_IF
+		
+	40: // Wait for inverter discharge done
+		IF _fbString.xShutdownDischargeAllowed THEN
+			_rPowerInverter := GVL_CONFIG.rAbsShutdownDischargePower;
+		ELSE
+			_rPowerInverter := 0.0;
+			_xEnableInverter := FALSE;
+			_iState := 45;
+		END_IF
+		
+		// Check for errors
+		IF _fbString.xError OR _fbInverter.xError THEN
+			_iState := 1000;
+		END_IF
+		
+	45: // Wait for shutdown of string to be done
+		IF (NOT _fbString.xInShutdownDischargeMode) AND _fbString.xOff THEN
+			_iState := 0;
+		END_IF
+	
+		// Check for errors
+		IF _fbString.xError OR _fbInverter.xError THEN
+			_iState := 1000;
+		END_IF
+		
+	1000: // Error state
+		_xEnableString := FALSE;
+		_xEnableInverter := FALSE;
+		_rPowerInverter := 0.0;
+		GVL_MODBUS.stModbusEMSComm.eBatteryStatus := E_BATTERY_STATUS.ERROR;
+		_iState := 1010;
+		
+	1010: // Wait for reset from error state
+		IF (GVL_MODBUS.stModbusEMSComm.diSetpointActivePower = 0) AND (NOT _fbString.xError) AND (NOT _fbInverter.xError) THEN
+			// Reset modbus error register
+			GVL_MODBUS.stModbusEMSComm.lwErrorBitmap := 0;
+			
+			// Reset modbus error flag
+			GVL_MODBUS.stModbusEMSComm.eBatteryStatus := E_BATTERY_STATUS.OFF;
+			
+			// Goto init state
+			_iState := 0;
+		END_IF
+		
+END_CASE
+
+	
+// Reset alarm confirmation
+IF _xConfirmAlarms THEN
+	_xConfirmAlarms := FALSE;
+END_IF]]></ST>
    </Implementation>
    <LineIds Name="MAIN">
-      <LineId Id="7" Count="6" />
-      <LineId Id="2" Count="0" />
+      <LineId Id="126" Count="55" />
+      <LineId Id="218" Count="0" />
+      <LineId Id="182" Count="0" />
+      <LineId Id="304" Count="0" />
+      <LineId Id="207" Count="2" />
+      <LineId Id="314" Count="0" />
+      <LineId Id="210" Count="2" />
+      <LineId Id="305" Count="1" />
+      <LineId Id="308" Count="0" />
+      <LineId Id="215" Count="0" />
+      <LineId Id="219" Count="1" />
+      <LineId Id="222" Count="0" />
+      <LineId Id="221" Count="0" />
+      <LineId Id="223" Count="1" />
+      <LineId Id="234" Count="1" />
+      <LineId Id="237" Count="1" />
+      <LineId Id="236" Count="0" />
+      <LineId Id="309" Count="3" />
+      <LineId Id="315" Count="1" />
+      <LineId Id="360" Count="1" />
+      <LineId Id="313" Count="0" />
+      <LineId Id="317" Count="0" />
+      <LineId Id="241" Count="0" />
+      <LineId Id="240" Count="0" />
+      <LineId Id="239" Count="0" />
+      <LineId Id="327" Count="0" />
+      <LineId Id="242" Count="1" />
+      <LineId Id="262" Count="0" />
+      <LineId Id="264" Count="0" />
+      <LineId Id="261" Count="0" />
+      <LineId Id="263" Count="0" />
+      <LineId Id="265" Count="0" />
+      <LineId Id="260" Count="0" />
+      <LineId Id="245" Count="0" />
+      <LineId Id="244" Count="0" />
+      <LineId Id="328" Count="0" />
+      <LineId Id="330" Count="2" />
+      <LineId Id="339" Count="0" />
+      <LineId Id="338" Count="0" />
+      <LineId Id="333" Count="3" />
+      <LineId Id="340" Count="3" />
+      <LineId Id="337" Count="0" />
+      <LineId Id="329" Count="0" />
+      <LineId Id="344" Count="1" />
+      <LineId Id="347" Count="12" />
+      <LineId Id="346" Count="0" />
+      <LineId Id="246" Count="2" />
+      <LineId Id="251" Count="0" />
+      <LineId Id="249" Count="1" />
+      <LineId Id="256" Count="1" />
+      <LineId Id="266" Count="0" />
+      <LineId Id="296" Count="0" />
+      <LineId Id="290" Count="0" />
+      <LineId Id="267" Count="0" />
+      <LineId Id="291" Count="0" />
+      <LineId Id="294" Count="1" />
+      <LineId Id="292" Count="1" />
+      <LineId Id="268" Count="0" />
+      <LineId Id="258" Count="0" />
+      <LineId Id="269" Count="1" />
+      <LineId Id="272" Count="0" />
+      <LineId Id="259" Count="0" />
+      <LineId Id="273" Count="3" />
+      <LineId Id="278" Count="3" />
+      <LineId Id="277" Count="0" />
+      <LineId Id="285" Count="0" />
+      <LineId Id="287" Count="2" />
+      <LineId Id="286" Count="0" />
+      <LineId Id="282" Count="1" />
+      <LineId Id="300" Count="0" />
+      <LineId Id="302" Count="1" />
+      <LineId Id="301" Count="0" />
+      <LineId Id="297" Count="2" />
+      <LineId Id="284" Count="0" />
+      <LineId Id="183" Count="2" />
+      <LineId Id="216" Count="1" />
+      <LineId Id="186" Count="6" />
+      <LineId Id="252" Count="1" />
+      <LineId Id="255" Count="0" />
+      <LineId Id="254" Count="0" />
+      <LineId Id="193" Count="9" />
+      <LineId Id="25" Count="0" />
    </LineIds>
  </POU>
 </TcPlcObject>
--- a/PLC/POUs/Sunspec/FB_PowerSupplySunspec.TcPOU
+++ b/PLC/POUs/Sunspec/FB_PowerSupplySunspec.TcPOU
@@ -268,7 +268,7 @@ CASE _iState OF
 			IF NOT _fbReadRegister.bError THEN
 				_iState := 40;
 				// Reading a register with scaling factor = value * 10^SF
-				_rWMax := _iWMax * EXPT(10,_iWMaxSF);
+				_rWMax := LREAL_TO_REAL(_iWMax * EXPT(10,_iWMaxSF));
 				
 				// Calculate power to write to register
 				_iWMaxLimPct := LREAL_TO_INT(rPower * EXPT(10,_iWMaxLimPctSF) / _rWMax);
@@ -444,8 +444,8 @@ CASE _iState OF
 			// If there was no error and the converter has no error continue
 			IF NOT _fbReadRegister.bError THEN
 				_iState := 65;
-				rActDCCurrent := WORD_TO_UINT(_awCurrentDCValues[0]) * EXPT(10,WORD_TO_INT(_awCurrentDCValues[1]));
-				rActDCVoltage := WORD_TO_UINT(_awCurrentDCValues[2]) * EXPT(10,WORD_TO_INT(_awCurrentDCValues[3]));
+				rActDCCurrent := LREAL_TO_REAL(WORD_TO_UINT(_awCurrentDCValues[0]) * EXPT(10,WORD_TO_INT(_awCurrentDCValues[1])));
+				rActDCVoltage := LREAL_TO_REAL(WORD_TO_UINT(_awCurrentDCValues[2]) * EXPT(10,WORD_TO_INT(_awCurrentDCValues[3])));
 			ELSE
 				// Read error register
 				_iState := 1000;
--- a/PLC/_CompileInfo/C2EFA9D3-F836-4688-55AF-5172A93B9E75.compileinfo
+++ b/PLC/_CompileInfo/C2EFA9D3-F836-4688-55AF-5172A93B9E75.compileinfo