Differences

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--- ccgx:modbustcp_faq [2019-12-23 11:41] – [7. Trouble shooting] mvader
+++ ccgx:modbustcp_faq [2020-01-06 12:48] – [6. Error codes and trouble shooting] mvader
@@ Line 67: / Line 67: @@
 Note that there is no difference between function code 3 and 4.
+==== 5. Mapping example ====
-==== 5. Error codes ====
-^Code^Name^Description^
-|0x01|IllegalFunction|The requested function is not supported.|
-|0x02|IllegalDataAddress|The Unit-ID is available, but one or more of the requested register(s) does not exist.|
-|0x03|IllegalDataValue|The requested quantity of registers is invalid. See the modbus specs, http://www.modbus.org/specs.php, for the limits per function code.|
-|0x0A|GatewayPathUnavailable|Unit-ID is defined in the mapping list, but there is no device found on the mapped port. Double check the Unit-ID mapping list in the excel sheet, and make sure that the device is properly connected to the CCGX, switched on, and that its data is available on the CCGX display.|
-|0x0B|GatewayTargetDeviceFailedToRespond|Requested Unit-ID not found in the mapping list. Double check the Unit-ID mapping list in the excel sheet.|
-==== 6. Mapping example ====
 The purpose of this example is to show how to interpret the information in the worksheets of the
 excel sheet containing the modbustcp mapping. This excel sheet is available for download from our website on the [[https://www.victronenergy.com/panel-systems-remote-monitoring/color-control#whitepapers|Color Control page]].
@@ Line 84: / Line 75: @@
 The ModbusTCP reply will contain 2302. Divide it by 10, as specified in cell E3, and then you have the voltage: 230.2 Volts AC.
-==== 7. Trouble shooting ====
+==== 6. Error codes and trouble shooting ====
+=== 6.1 The common cause: Unit-ID / Register combination ===
+In case a certain read or write is not successful, most likely there is an issue in the unitid/registerid combination.
+Besides double checking the mapping, there are two ways to see where the error lies. One is to check the last error as shown in the GX Device menus. And secondly you can look at the error code as is visible on (most but not all) PLCs. See the two sections below for details.
+=== 6.2 Looking up the last ModbusTCP Error on the GX Device===
 To see why a certain register is not available, use the Settings -> Services -> ModbusTCP menu. It shows the last error, and reason for that error.
-==== 8. Support ====
+TODO ADD PICTURE
+=== 6.3 Error codes ===
+These error codes are returned by our software to the PLC; and most PLC software tools allow seeing them.
+^Code^Name^Description^
+|0x01|IllegalFunction|The requested function is not supported.|
+|0x02|IllegalDataAddress|The Unit-ID is available, but one or more of the requested register(s) does not exist.|
+|0x03|IllegalDataValue|The requested quantity of registers is invalid. See the modbus specs, http://www.modbus.org/specs.php, for the limits per function code.|
+|0x0A|GatewayPathUnavailable|Unit-ID is defined in the mapping list, but there is no device found on the mapped port. Double check the Unit-ID mapping list in the excel sheet, and make sure that the device is properly connected to the CCGX, switched on, and that its data is available on the CCGX display.|
+|0x0B|GatewayTargetDeviceFailedToRespond|Requested Unit-ID not found in the mapping list. Double check the Unit-ID mapping list in the excel sheet.|
+==== 7. Support ====
 The recommended method for report on ModbusTCP questions is to use the [[https://community.victronenergy.com/spaces/31/index.html|Modifications section on Victron Community]]. Its frequently visited by many people using ModbusTCP and other methods of integrating with Victron products.
@@ Line 93: / Line 107: @@
 Direct company support is only offered on a limited basis. For such support, contact our Victron representative.
-==== 9. FAQ ====
+==== 8. FAQ ====
 === Q1: Which products can be interfaced via Modbus TCP? ===