My PLC works as modbus tcp slave and Scada exchange data via modbus tcp (client)

From time to time scada immediatly stop reading datas because of timeout.

When I check mb_server status then status = 16#7002

When I restart scada nothing is changed - there is no communication via modbus tcp.

When I restart mb_server by disconnecting and connecting again then after about 30 seconds scada works ok.

I don't know why after reseting mb_server status = 16#7002 for 30 seconds ?

And why sometimes modbus tcp slave in plc fails.

Hello 

1- Did You Use Clock Source in of the Request source of the Modbus Server TCP IP ? as I understand from your Query you are not using...If yes 

2- Please check the PLC or the SCADA is connecting with different station in same time...

3-If you have the only SCADA system connected with the S7-1200 PLC ...you have to check your scada communication setting because it is not good to wait 30 sec to start communication with PLC

Hello Viper,
I recommend to evaluate the outputs of MB_SERVER in your program. Store STATUS when ERROR=TRUE. Then you can see what happened.

Regards,
Kaulquappe

MAZENJER

1- Did You Use Clock Source in of the Request source of the Modbus Server TCP IP ? as I understand from your Query you are not using...If yes 

2- Please check the PLC or the SCADA is connecting with different station in same time...

3-If you have the only SCADA system connected with the S7-1200 PLC ...you have to check >> your scada communication setting because it is not good to wait 30 sec to start communication with PLC

1: I don't understand what You mean with "Clock Source" oin Modbus Server
2: Scada is comunicating with different station ID but in my program there are 4 mb_server block with different port for each one i.e 502, 503, 504, 505 and for port 502 ID=1, 503 ID=2, 504 ID=3....
3. I don't know why after disconnecting and connecting there is status = 7002 for about 30 seconds.

I'm using plc 6ES7 214-1AG40-0XB0 with firmware 4.1. MB_Server is in version V2.0 [Instruction V3.1]

I'm using Tia Portal V13 SP1 with all updates

Kaulquappe

Hello Viper,
I recommend to evaluate the outputs of MB_SERVER in your program. Store STATUS when ERROR=TRUE. Then you can see what happened.

Regards,
Kaulquappe

 There is no error but only status = 7002. What should I store when error occurs ? What kind of information ?

Maybe I should upgrade MB_SERVER block function to the newest version ?

What are improvments in new version from 2.1 or 3.0 ?

AS suggested Kaulquappe

 You should store the STATUS value of MB_SERVER FB into a variable through the flag ERROR.

When ERROR is true, store STATUS in variable.

In your monitoring program you can't see if an error is happening because status change at a rate that is almost impossible to catch and show in the monitoring software (Tia or portal).

Then using the online help for your FB MB_SERVER, you can see the meaning of HExadecimal value of STATUS when error occourred.

Hope this help

Here I have problem because modscan or scada can't read registers.

There is no error or status with error.

MB_SERVER think that there is connection with client but there are no any connections.