# Error Invalid parameter(s) Modbus 750-652

**URL:** <https://www.wago.community/t/error-invalid-parameter-s-modbus-750-652/2416>\
**Category:** CODESYS\
**Created:** [November 17, 2025, 10:49am UTC](https://www.wago.community/t/error-invalid-parameter-s-modbus-750-652/2416 "2025-11-17T10:49:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Hades00](https://avatars.discourse-cdn.com/v4/letter/h/e36b37/32.png) [@Hades00](https://www.wago.community/u/Hades00)\
**Post date:** [November 17, 2025, 10:49am UTC](https://www.wago.community/t/error-invalid-parameter-s-modbus-750-652/2416/1 "2025-11-17T10:49:13Z")

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Hello,  
i am trying to control a Novocon S actuator with a 750-8110 PLC using a 750-652 modul, i used FBMbMasterSerial function block, the Baud rate is set to 9600 in the Modul as well as the Function block, databits is 8 on both, however whenever i run the program in the plc the variable “xIsConnected” is false and it shows an error “Invalid Parameter(s)”. the actuator is functional (configured in Novocon Configuration tool).  
does anyone have an idea what can be a solution.  
Best Regards,  
hades00

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**Author:** ![antauva](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@antauva](https://www.wago.community/u/antauva)\
**Post date:** [November 17, 2025, 1:56pm UTC](https://www.wago.community/t/error-invalid-parameter-s-modbus-750-652/2416/2 "2025-11-17T13:56:55Z")

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Hello,  
Interface of FbMbMasterSerial is  
FbMbMasterSerial (FB)

**Interface variables**

| Scope | Name | Type | Initial | Comment | Inherited from |
| --- | --- | --- | --- | --- | --- |
| Input | `xConnect` | `BOOL` | | | FbBaseInterface |
| `I_Port` | `WagoTypesCom.I_WagoSysComBase` | | Name of the Interface (e.g. ‘COM1’, ‘SER7.2’, ) | FbBaseInterface | |
| `udiBaudrate` | `UDINT` | | Baudrate (9600 = 9k6) | FbBaseInterface | |
| `usiDataBits` | `USINT` | | Number of Bits per frame (5..8) | FbBaseInterface | |
| `eParity` | `WagoTypesCom.eTTYParity` | | Parity | FbBaseInterface | |
| `eStopBits` | `WagoTypesCom.eTTYStopBits` | | Number of Stop-Bits, see note (1) | FbBaseInterface | |
| `eHandshake` | `WagoTypesCom.eTTYHandshake` | | TYPE of handshake (XON/XOFF, etc) | FbBaseInterface | |
| `ePhysical` | `WagoTypesCom.eTTYPhysicalLayer` | | RS232, RS422, RS485, etc | FbBaseInterface | |
| Output | `xIsConnected` | `BOOL` | | | FbBaseInterface |
| `xError` | `BOOL` | | | FbBaseInterface | |
| `oStatus` | `WagoSysErrorBase.FbResult` | | | FbBaseInterface | |
| Input | `eFrameType` | eMbFrameType | eMbFrameType.RTU | | |
| `tTimeOut` | `TIME` | TIME#200ms | | | |
| Inout | `utQuery` | typMbQuery | | | |
| `xTrigger` | `BOOL` | | | | |
| `utResponse` | typMbResponse | | | | |

where you are see an error “Invalid Parameters”?

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<div class="post-metadata">

**Author:** ![Hades00](https://avatars.discourse-cdn.com/v4/letter/h/e36b37/32.png) [@Hades00](https://www.wago.community/u/Hades00)\
**Post date:** [November 17, 2025, 2:11pm UTC](https://www.wago.community/t/error-invalid-parameter-s-modbus-750-652/2416/3 "2025-11-17T14:11:00Z")

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when I run my program i get “error = true”, and when I open the oStatus it says the error descrition and it says “ Invalid Parameter(s)”. I assigned the I\_Port to the 750-652 Modul name “\_750\_652\_24” I dont know if thats the problem.

 ![Screenshot 2025-11-17 150945](https://us1.discourse-cdn.com/flex016/uploads/wago/original/2X/4/4143581e8d9e657f1c6258b1b37db01a05d26bae.png)

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<div class="post-metadata">

**Author:** ![antauva](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@antauva](https://www.wago.community/u/antauva)\
**Post date:** [November 17, 2025, 2:37pm UTC](https://www.wago.community/t/error-invalid-parameter-s-modbus-750-652/2416/4 "2025-11-17T14:37:19Z")

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Please show all input variables what you are use. for assignment I usually use pointer something like that Port1 := ADR(\_750\_652\_24) and then I\_Port := ^Port1,  
Check settings in the Wago I/O check or use default values.

 ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/2X/e/e81f6959070740fa7ed902638ef4b0036f8bacfc.png)