HenkAnalfabeet

Kaulquappe

Hello Henk,
Pin 4 of CP341 is R- and it must be connected to - of the communication partner.

>>This was initially done wrong by me, I can now confirm that pin 4 goes to the neggative terminal (B-) of my Servo (and 11 goes to A+)

And some simple questions....
Did you set M120.7 in the variable table?

>>I've seen M120.7 in the send part of the program, I have not set it anywhere, will do some reading up on the forums / with the manual to see what is needed here (can this be the cause of the problem?)

Did you check the DONE counter and the errror counter in DB40?

>>DB40 has all registers showing as 16#00

And you send 32 Byte, a read job consists of 6 Bytes! Your error counter should increase and youwill get the error message 0518.

No error codes, where have I defined (read copied from the example project) 32? I'll change it


Regards,
Kaulquappe

Thanks!

 Hi all,

I am having a similar situation where there is no led indication in CP. Checked the connection and found ok. In program send request is getting high. But it is not getting reset as neither done nor error is coming. Plz guide.

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Split from CP341 Modbus Master, no comms, no lights, but no faults either.

Hello,

for first pls tell us what MB protocol you want implement, if all HW requirements are solved (HW dongle depended to protocol), correct CP341 settings (protocol, same speed as Slave/s), what automation SW you're using, maybe also type of CP341.

Hi Mr.Duris,

We are having CP 341 RS422/RS 485 model. We use 2 wire half duplex mode of communication, speed of 9.6 Kbps. After the problem, We tried changing the CP also but still no effect. I tried to check the diagnostic buffer of CP but there was no error. Status is Module is OK.

Our connection in CP is 

Pin 4  is -ve

Pin 8 is Gnd

Pin 11 is +ve

We are using simatic manager step 7 software.

Regards

Surendhar M

Hello,

without know other settings as I asked, hard to say where problem can be. If you can, post screenshots (zipped) of your code with RK instructions (online) and info which Slave device you want request, what data you expect receive from it.

AutoGen_148962

Hi Mr.Duris,

We are having CP 341 RS422/RS 485 model. We use 2 wire half duplex mode of communication, speed of 9.6 Kbps. After the problem, We tried changing the CP also but still no effect. I tried to check the diagnostic buffer of CP but there was no error. Status is Module is OK.

Our connection in CP is 

Pin 4  is -ve

Pin 8 is Gnd

Pin 11 is +ve

We are using simatic manager step 7 software.

Regards

Surendhar M

 Which configuration are doing with CP341(MODBUS MASTER/SLAVE)

IF you are using modbus master try this Docs

Hello,

you can also look to this manual (attachment).

Thank u both. 

We are using Modbus master configuration.

I am not able to upload the program as it is more than 30MB. 

My setting is RS485 2 wire half duplex. I have same blocks as used in sample programs. I have 4 areas from where modbus data are coming. 3 areas are able to send data. Only one area is not sending data. In logic I can see that send request bit is always high in problematic area whereas in FB of other areas send request is fluctuating. 

I checked the voltage level between A and B and found to be 2.5V. In manual it's mentioned that it should be 5V. Will it be a reason? We are getting data from belt watch controller.

Hello;

Would it be possible for you to give us a diagram of your network, showing the nodes, a typical node wiring (specially the ground connection) and the termination resistances? Modbus can be very forgiving as far as topology is concerned (it is relatively slow) but there are some basic rules that can trip you up if you do not respect them .

Hope this helps,

Daniel Chartier

Hi all,

Problem solved by downloading the Instance DB 584. This is for send_PK

Regards

Surendhar M