Bring Siemens tags into a CompactLogix PLC

[Phil Buchanan]

Hi yes it is a hmi but cheaper than a datastation and will act as a gateway.just mount it in the panel and dont use the hmi part

1+

I have done this many times in low budget projects to get the comms needed for a cheap price and just put some simple comms status graphics on the small red lion HMI.

This is also much more reliable than a PC with kepware running on it as the kadet or data station is a hardware solution and not at the mercy of windoze.

 

[JOLTRON]

How often do you need to update data on the screen? If compact logix can receive data from a tcp/ip stream you may not need any hardware. Just programing on both machines. I assume someone has passed data back and forth this way.

 

[VSeaver]

How often do you need to update data on the screen? If compact logix can receive data from a tcp/ip stream you may not need any hardware. Just programing on both machines. I assume someone has passed data back and forth this way.

I would like the data real time. That would give me a true OEE calculation. The data I am trying to retrieve is line speed of the Siemen's machine. I may try to get other data but the line speed is the most important. This line speed would then be calculated with the amount of product coming off the CompactLogix machine and the operating time to give me my Performance.

 

[VSeaver]

1+

I have done this many times in low budget projects to get the comms needed for a cheap price and just put some simple comms status graphics on the small red lion HMI.

This is also much more reliable than a PC with kepware running on it as the kadet or data station is a hardware solution and not at the mercy of windoze.

So, if I install the Kadet, I then can retrieve my Siemens machine line speed from it and put it in the CompactLogix plc? I currently have an Allen Bradley HMI on the CompactLogix machine. I also have a HMI in my office that has the Siemens machine line speed on it.

 

[cjd1965]

you should be able to create a map inside the kadet.

Read Siemens tag(s) and write to the clx tag(s)

Read clx tag(s) and write it to siemens tag(s)

Your red lion distriutor should be able to help you in the form of a "demo"

Best of luck

 

[VSeaver]

you should be able to create a map inside the kadet.

Read Siemens tag(s) and write to the clx tag(s)

Read clx tag(s) and write it to siemens tag(s)

Your red lion distriutor should be able to help you in the form of a "demo"

Best of luck

Thanks for the help. Much appreciated.

 

[mk42]

Yes. They are both on our network. I can view both of them from my desk. The info I want from the Siemens machine is the line speed. So this will have to be 'real time'. If I can get this tag imported somehow into the CompactLogix plc, I then can take that as well as the parts count coming out of the CompactLogix machine and calculate all my OEE values.

The Siemens machine is the main machine and the CompactLogix machine is the packaging machine. The Siemens machine feeds the CompactLogix machine.

"Real Time" is relative. The other method discussed in this thread (an HMI) typically doesn't read data faster than 100ms anyway, and often much slower than that (once a second). Sending TCP/IP messages should be able to match that, unless your PLC scan times are even longer.

OEE type information needs to update fast enough to reflect the real situation of the system, but if your line speed is changing multiple times a second, I would expect you have bigger problems than data updates.

 

[Thomas_v2]

Depends on how much time you want to invest, if you can do TCP communication with your CompactLogix plc, then it should be possible to code the parts of the S7 protocol in software, so that you can get access to the memory areas inside the S7 plc - without changing anything in the S7 plc.
All you need is the memory address inside the S7 plc (Mx.y / DBx.DBy)

I can send you a code example written in ST which uses the network functions from the Oscat library as network layer.

 

[Pete.S.]

If you need line speed I suggest just doing it with an analog 4-20mA out from the Siemens to the AB PLC.

It's the most compatible way to communicate and the fastest way to get it up and running. And it's very easy to troubleshoot.

And in the future if one system is upgraded or changed it will still work.

Otherwise modbus tcp is the most compatible communication protocol so I would use that for inter-PLC communication if it can't be hardwired. Going over a HMI is slow and not future proof. However that said, modbus tcp on S7-300 is not free and a bit of a hassle to program (depending on your needs).

 

[VSeaver]

Depends on how much time you want to invest, if you can do TCP communication with your CompactLogix plc, then it should be possible to code the parts of the S7 protocol in software, so that you can get access to the memory areas inside the S7 plc - without changing anything in the S7 plc.
All you need is the memory address inside the S7 plc (Mx.y / DBx.DBy)

I can send you a code example written in ST which uses the network functions from the Oscat library as network layer.

I have plenty of time. This project is just something I want to play with to see if it can be done. That way it can show the people with the check books the possibilities of getting software that can do all this. As far as TCP communication. Correct me if I am wrong, but both machines are on our network through Ethernet. Is that the same thing? If so, I was under the impression that AB and Siemens have different protocols so I will need some sort of bridgeway in between to decipher the code. If you got code that does this that is fantastic. I would much rather do this without having to buy equipment.

 

[VSeaver]

If you need line speed I suggest just doing it with an analog 4-20mA out from the Siemens to the AB PLC.

It's the most compatible way to communicate and the fastest way to get it up and running. And it's very easy to troubleshoot.

And in the future if one system is upgraded or changed it will still work.

Otherwise modbus tcp is the most compatible communication protocol so I would use that for inter-PLC communication if it can't be hardwired. Going over a HMI is slow and not future proof. However that said, modbus tcp on S7-300 is not free and a bit of a hassle to program (depending on your needs).

I actually thought of this over the weekend. The problem I have is that the Siemens plc is pretty far away from the AB plc.

 

[mk42]

As far as TCP communication. Correct me if I am wrong, but both machines are on our network through Ethernet. Is that the same thing? If so, I was under the impression that AB and Siemens have different protocols so I will need some sort of bridgeway in between to decipher the code. If you got code that does this that is fantastic. I would much rather do this without having to buy equipment.

You ask if TCP and Ethernet are the same thing, and the answer is "kinda". Ethernet is something of a layered concept. The bottom layers (like the physical layer) are where Ethernet itself resides. Above Ethernet are a variety of layers, with different protocols. The networking layer is layer 3, where IP addresses are defined. TCP or UDP is at layer 4. EtherNet/IP is built on top of that. See the wikipedia link below for more info.

https://en.wikipedia.org/wiki/OSI_model

AB controllers typically support Ethernet/IP for IO control. Siemens PLCs typically support Profinet for IO control. However, that doesn't mean that it is the only protocol they support. Siemens PLCs can send TCP or UDP packets directly. Depending on what hardware you are using, look for the T_Send/Recv instructions or AG_Send/Recv. On the AB side, the newer ethernet cards support it as well, via a MSG instruction.

 

[Pete.S.]

I actually thought of this over the weekend. The problem I have is that the Siemens plc is pretty far away from the AB plc.

You can run a 4-20mA signal very far, many thousands of feet actually.


How far is far in your case?

 

[VSeaver]

You ask if TCP and Ethernet are the same thing, and the answer is "kinda". Ethernet is something of a layered concept. The bottom layers (like the physical layer) are where Ethernet itself resides. Above Ethernet are a variety of layers, with different protocols. The networking layer is layer 3, where IP addresses are defined. TCP or UDP is at layer 4. EtherNet/IP is built on top of that. See the wikipedia link below for more info.

https://en.wikipedia.org/wiki/OSI_model

AB controllers typically support Ethernet/IP for IO control. Siemens PLCs typically support Profinet for IO control. However, that doesn't mean that it is the only protocol they support. Siemens PLCs can send TCP or UDP packets directly. Depending on what hardware you are using, look for the T_Send/Recv instructions or AG_Send/Recv. On the AB side, the newer ethernet cards support it as well, via a MSG instruction.

I am fairly new at programming in Step 7. I do better in AB. I will have to find some manuals on how to program in Step 7. This is beyond me. I would love to learn more about Siemens programming because I believe it has more capabilities than AB. Just a learning curve. Thanks for your help.

 

[VSeaver]

You can run a 4-20mA signal very far, many thousands of feet actually.


How far is far in your case?

Its definitely not that long of a run. Its just the location of the 2 machines. I would have to run conduit up to the ceiling and back down again. If I can't figure out the programming side like mk42 was telling me about, I may have to go this route. I was also thinking of putting a rpm sensor on the Siemens machine and put that in to my AB machine as an analog signal. Thanks for your help.