HI,

I`m trying communicate a keypad with number and directional using the rs485 to a PLC s1200, that keypad was working in a PLC Schneider and I don`t have access, We replace the PLC for Siemens and now I`m struggling to communicate with CPU 1214C with a card CB 1241.

Thank you!

Hello. 

flpantunes

HI,

I`m trying communicate a keypad with number and directional using the rs485 to a PLC s1200, that keypad was working in a PLC Schneider and I don`t have access, We replace the PLC for Siemens and now I`m struggling to communicate with CPU 1214C with a card CB 1241.

Thank you!

Consider giving the forum information that can be acted on. Think about how you will inform the forum on things like..
* Electrical connections: previous and now
* Configuration of hardware in the program
* Instructions used in the user program  
* How the program looks like
* What fault codes are generated 
* Observations of status lamps or device behaviour
* How is a test made
* How do we know that the keypad still works

Can the functionality of the keypad be verified without the PLC?

There is no mention of which protocol is being used. 
(HINT: RS485 is not the answer I am looking for.)

~

Mr Duris, you were missed. 
It is a pleasure to have you visit us again with your contributions. 

Duris_I

Hello,

only little addition to good advice from qwazee. As he also mentioned, RS485 doesn't mean automatically Modbus protocol. This is very important to know what protocol is used, although I expect Schneider Modbus capable generally.

I would have guessed that ASCII characters are transmitted.
(Yes .. even if the old PLC was Modicon.)
A header and footer character may even be there.
Simply -- we do not know what the device specification is.

* Electrical connections: previous and now

Previous connections in Schneider PLC model TM218LDA60DRN:

D0= Keypad rs485 B    D1= Keypad rs485 A

Now PLC Siemens, CB1241 6ES7 241-1CH30-1XB0:

TA,T/RA= Keypad rs485 A      TB,T/RB= Keypad rs485 B

* Configuration of hardware in the program

* Instructions used in the user program
* How the program looks like
* What fault codes are generated

The Light TB flash 3 times each second and the keypad just show no communication

* Observations of status lamps or device behavior
* How is a test made

I have used in the Schneider and still have the PLC to connect and test.

* How do we know that the keypad still works

I can connect in the Schneider and test, also I have two Schneider and two Keypad to test 

Below I have attached A video and Some pics to take a look.

If need more information let me know how can I get that for you.

Hello,

That is what I found in the Schneider PLC, and I founded this tester for Modbus I`ll try see what I can get from that.

Here one attachment.

@Duris: Would that be an extended Modbus register address that I see (400_001)?

@flpantunes: Did I miss it?.. did you place down some sample of your code yet? I am interested to see if the communication link is established. If not some status would be helpful.

There is also a possibility that the A and B is swapped around. One of the resident Modbus experts has mentioned before that the documentation of the channels got mixed up when the specification was put up in historic times.

I am also wondering how many devices do you have connected when trying to have the Siemens PLC link to the keypad. heck... Do we even know which device is the master and what the modbus addresses are of the devices?

EDIT: Why do I see 4 wire device in the "tester"? What is this "tester"?

Here the Code that I have to try communicate, is an archive for TIA V13, and I already swap the A and B and still the same, the test in the picture is what @Duris_I mentioned about Hercules, so for now forget about the test because I not tested with. Here the Link For Code. 

[snip]

I just have the Keypad connected direct to PLC nothing else.

The picture Below is the only config with the Schneider and Keypad

2 wire