Hello.

I have prepared the project based on ET1512 SP F-1 PN cpu with CM PTP (6ES7 137-6AA00-0BA0) wchich I had some bad problems when starting up.

The CPU is communicating 7 ATV320 inverters on modbus RTU.

Now it's time to extend the project with another 5 inverters.

As I had problems with starting up the basic project I have decided to extend the electrical panel by adding the IM 155-6 PN ST with 2 digital inputs , 2 digital outputs and another CP PTP (6ES7 137-6AA00-0BA0)

I have redid the program by simply coping the working project OB networks ( the working one ) and reduing it that the sequence of the calls for communication should work in pararel. 

There are two calls of MODBUS_COMM_LOAD using different instance DB's (DB60 and DB244)

For each call of MODBUS_COM_LOAD the software uses the proper hardware ID of the CM PTP (HW id: 260 for CM connected to the CPU, and HW id 377 for CM connected to IM 155-6 PN )

The MODBUS_MASTER are using different instances for each CM PTP calls.

The problem starts wen i try to start the seqence of calls for CM PTP connected to IM 155-6 PN.

On network number 1 ( CM connected to CPU i'm starting to get errors 80C8 on read operation and 818D on write operation.

On Network 2 ( CM connected to IM 155 ) I'm getting the same errors and sommetimes whole sequece finnishes with error 8200 interface buisy .

I'm getting little bit crazy . For each network ( CM card ) , the instances of MODBUS_COM_LOAD are different , when i checked the parameters inside the MODBUS_MASTER DB's the hardware ID's of the interfaces are different ant properly set.

The seqence of the modbus communication is called in OB31 .

Any ideas what could be the mistake ?

Is it possible for two CM PTP for ET200SP to work in pararell ? Or they have to work one by one ?

Ps. I did a checking if there are no two comunication requests same time on each network.

Cześć.

Thanks for reply.

For the test i have moved the whole sequence of communication from OB31 to the FB called in main OB1 .

As the CPU program cicle time is arout 60ms the only result is that whole communication cicle time on network 1 rised up from less than one second to around 2 seconds. I need to call the MODBUS_MASTER 14 times , 7 read registers operations , 7 write registers operations, to make sure that i have full control about calls I have wrote 14 calls of MODBUS_MASTER. Each call is triggered by done or error status of the previus call, so for each data exchange using OB1 at least 3 CPU cycles are needed.

The result is only extending the time, the errors are the same.

The wiring on the modbus network is independent, I undertand that there can't be two masters on modbus RTU network.

For the second network i don't care so much about communication cicle. If it will be neccesary i will play wit it later. First thing to make it working.

If anybody have some suggetions please help.

First CM PTP was working ok for last 9 moths.

After updating the project when the comminication of network 2 if off ( MODBUS_COMM_LOAD done ok but the communication is not triggered) I get nearly no errors on network 1, less than 0,1 % of the communication attepts finishes with error 80C8 - "The slave does not respond within the set time".

When i start the communication on the second CM PTP i starting to get the errors on Network 1

80C8 - "The slave does not respond within the set time" - on read registers.

818D - "The area addressed by DATA_PTR is longer than the DB, or the area addressed is too small for the number of data bytes to be read or written." - on writing the registers.

More than 1,5 percent of errors on network 1.

The network on CM PTP number two goes crazy. I get the errors :

80C8 - "The slave does not respond within the set time" - on read registers.

818D - "The area addressed by DATA_PTR is longer than the DB, or the area addressed is too small for the number of data bytes to be read or written." - on writing the registers.

8200 - The interface is busy with an ongoing request.

Hello.

Seems that the problem is somwhere elese.

The network 1 works fine with no errors, and when the network 2 starts it gives info about wrong data lenth and so one.

There are only ATV320 inverters in the system, so the data is exaclty the same.

I add an attachement with most important parts of the program.

I didnt added screens of all the triggers and all the MODBUS_MASTER calls , but the idea is the same , i did 5 times check of the double modbus master triggerring, i didn't found nothing.

If theres one condition which I have found and have no idea how to solve when MODBUS_MASTER instances are called the same time for different CM PTP the system goes crazy.

I'm trying to figure out why ;) .

Hello.

The only memory overlaps are for purpouse, the bits representing MODBUS_MASTER buisy status are overlaping the word from which i count if there are no double reqests of communication. If it happens , alarm bit is set.

The bool on function enable was used to restart the communication when the MODBUS_MASTER was freezing on buisy status. I's not used anymore. The bit was moved to data table "waists" wchich I usually remove after finnishing the tests of the software and clean all the uses.