s7-1200 - what communication would you choose?

rQx · May 26, 2015

Hi!

I have standard cabinet with a s7-1200 that we produce and send to customers. Naturally sometimes there will be companies that want to access my PLC with their system (scada, dcs, other PCLs etc etc).

We can change the configuration for certain customers but what communication would you go for as a standard to avoid all questions a reprogramming?

Since I have a s7-1200 I would think something like this.

1. They can access it with Siemens products, like a Siemens scada system or a Runtime product. This demands no programming from my part.

2. They can use GET and PUT commands in their system to control and monitor our system, I will provide a heartbeat for their outputs to my control to ensure the communication when they control something using PUT.

3. They can use an OPC client, this doesn't demand programming from my part.

4. I program a Modbus TCP/IP aswell.

Is there something else you would integrate aswell? I'm not that familiar with communication between diffrent systems so please let me know if I miss something out.

/Tim

mk42 · May 26, 2015

rQx said:
Hi!

I have standard cabinet with a s7-1200 that we produce and send to customers. Naturally sometimes there will be companies that want to access my PLC with their system (scada, dcs, other PCLs etc etc).

We can change the configuration for certain customers but what communication would you go for as a standard to avoid all questions a reprogramming?

Since I have a s7-1200 I would think something like this.

1. They can access it with Siemens products, like a Siemens scada system or a Runtime product. This demands no programming from my part.

2. They can use GET and PUT commands in their system to control and monitor our system, I will provide a heartbeat for their outputs to my control to ensure the communication when they control something using PUT.

3. They can use an OPC client, this doesn't demand programming from my part.

4. I program a Modbus TCP/IP aswell.

Is there something else you would integrate aswell? I'm not that familiar with communication between diffrent systems so please let me know if I miss something out.

/Tim

I think you hit most of the communication options. I would add 2 more possibilities:

5. use raw TCP open socket communication, with T_send/recv_C. This is great for communicating to PC based systems that don't natively have PLC communication drivers like you mentioned in option 1. However, support for this option isn't as common in PLC's, but it is becoming more standard with time.

6. If you are communicating to another S7 PLC, I-Device is a great option. It basically allows one PLC to act as a Profinet slave to the other one, while still being able to control its own IO.

I think your option 1 or 3 would probably be the easiest to implement for you, and probably for any HMI/SCADA system they want to use. Many HMI's will have a Siemens driver available, and if they don't they should support OPC. Note that since the 1200 doesn't support OPC natively, you will need an OPC Server to grab its data to share with the HMI acting as an OPC client.

rQx · May 27, 2015

mk42 said:
I think you hit most of the communication options. I would add 2 more possibilities:

5. use raw TCP open socket communication, with T_send/recv_C. This is great for communicating to PC based systems that don't natively have PLC communication drivers like you mentioned in option 1. However, support for this option isn't as common in PLC's, but it is becoming more standard with time.

This could also be a good option, since I have to make blocks in my programming I can descide what tags they should have access to, unlike the GET/PUT where they basicly can access everything.

I thought T_Send/recs_c was a Siemens "thing" but it's universal?

mk42 said:
6. If you are communicating to another S7 PLC, I-Device is a great option. It basically allows one PLC to act as a Profinet slave to the other one, while still being able to control its own IO.

You are right, this has become available since firmware 4? I haven't got the opportunity to test it thought. When I configure it for I-device, will all s7 masters be able to read it? Or do they have to be a new firmware aswell?

mk42 said:
I think your option 1 or 3 would probably be the easiest to implement for you, and probably for any HMI/SCADA system they want to use. Many HMI's will have a Siemens driver available, and if they don't they should support OPC. Note that since the 1200 doesn't support OPC natively, you will need an OPC Server to grab its data to share with the HMI acting as an OPC client.

Yes, det customer have to buy a OPC server if necesary but I think if they have a OPC client they should know where to get one.

The option 1-3 demands no programming so they are very easy to implement.
Since modbus is a very common protocol aswell I think this is a good one to implement. If they want RTU they can always buy a converter from TCP/IP.

Thanks for your suggestions, much appreciated!

/Tim

s7-1200 - what communication would you choose?

rQx

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mk42

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rQx

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