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Dear All,

Could you please tell me what is the cause of this error? I am using Siemens CP341 and Modbus master through RS-485 to Flowcomputers. I am getting an error in Module Information of CP-341.

Error: Event 1 of 9: Event ID 16# F1C8:0E43
IF 1: Slave Address 0 (= Broadcast) not permitted with this function code.
Incoming event.

Could anyone help to solve this problem?

Modbus functions that return values (read functions) cannot be used with broadcast address.

Could you please explain briefly? I am trying to solve this problem. In flow computer, Modbus ID is set as 4 and in CP341 as well as in flow computer TXD, RXD is blinking.

Please help me to find a solution for this.

Thanks and Welcome.

Ajith

Hello,

The state of the lights is not enough to determine the cause of the failure.

The first message you posted indicated the function was attempting to communicate with a slave device at address 0. Address 0 is reserved for broadcast type messages.

If the function you are attempting is a "read" function it will fail using address 0.

If the function is a write function, it might succeed depending on the function type, register address, data value and slave device MODBUS implementation.

Without a dump of the message request/response stream I can not tell you exactly what is in error.

I would:
1. Verify the address the master is using to communicate with the slave is the address of the slave. You say it is 4 but the error message in the first post said it was 0.
2. Check the function code used in the message. (Supplying this information would help)
3. Verify the slave does contain the address range you are attempting to read/write.
4. Verify the slave addresses in all the flow computers on this 485 line are configured to different addresses.

Or post a stream dump of the request/response data bytes.

HTH,

Mark
http://www.hmisys.com

Regardless of what the Slave node address is set to, the Master appears to be sending 0 in the Node Address field, which is not allowable for read functions.

To resolve this, you'll need to set the target slave node address to 4 on the message originating from the master.

If still no luck, you should download portmon (free) and do a capture of the communications.

http://technet.microsoft.com/en-us/sysinternals/bb896644.aspx

Be sure to select the Options, Show Hex menu item.

You could also try another Modbus Master. Automated Solutions offers several Modbus Master products that can assist in troubleshooting. Free, 30-day trial versions are available for download.

Also, flow computers generally implement a specialized form of Modbus, which need special handling from the Master side. Automated Solutions products support many flow computer schemes.

Mark
http://www.automatedsolutions.com

Hello,
Not all MODBUS function codes allow a broadcast slave address of 0. Make sure the slave address is set to the flow computer MODBUS address.

Good luck,

Mark
http://www.hmisys.com

http://www.fultek.com.tr/index_dosyalar/Fultek_Modbus_Rtu_server.zip