SLC-504 communication with S7-300

[Mushu 0]

Hi, We have a plant with an Allen Bradley PLC; this is communicating with an Intouch trhough RS-232. A new machine is going to be implemented in the plant; it has a Siemens S7-300 PLC. The programme is ready to communicate through Ethernet (functions "AG_SEND" and "AG_RECV" are used). I asked to some colleges and they think the existing PLC will not communicate properlly with Ethernet. Do you have any idea how could it be done? I am completly lost in this. thanks

[jstolaruk 9]

Seeing as how your 5/04's ch0 port is tied up talking to the Intouch display, I believe your only recourse is to upgrade the 5/04 to a 5/05 for the Ethernet capability. As far as the two CPUs talking to each, that I'm unsure of. Edited 21 Sep 2005 by jstolaruk

[Mushu 0]

We could upgrade the CPU, but do you know wich functions would be needed? Would it work with a Siemens?

[jstolaruk 9]

could you expand on "a Siemens"? Edited 21 Sep 2005 by jstolaruk

[Mushu 0]

I think changing "our" PLC with a Siemens PLC is not a solution. My company is a Rockwell integrator, so they would not accept this solution. We could upgrade the SLC-504 with a SLC-505, but I am new with Allen Bradley PLC's, so I don't know wich functions I would have to use, or if it would work.

[jstolaruk 9]

You're a Rockwell Integerator and purchased machine with Siemens control system? lol, someone goofed. Swapping out the 5/04 for a 5/05 is a couple of minute job.

[Mushu 0]

jajaja, I think I did not explain it well; We are Rockwell integrators, and our customer (we put the Allen Bradley PLC) has bought the machine with Siemens. Nobody here has experience in communicating Siemens with Allen Bradley, so we don't know what is better: PROFIBUS-DP, Ethernet???? and nobody knows if it would work. thanks

[Mushu 0]

I have been talking with Allen Bradley technical support and he told me that Ethernet would not be a good idea. Allen Bradley Ethernet uses their own protocol to communicate with Allen Bradley products; and the technical support doubted that the Siemens Ethertnet cards will able to communicate with them. So they think PROFIBUS would be a better solution. and the Siemens PLC prefers Ethernet. What do I do?

[jstolaruk 9]

Why do they need to talk to each other?

[Mushu 0]

One of the PLC controls the CIP center and the other controls some part of the process. During CIP they need to know if they are ready, one command valves (they are connected to the other PLC), and to know if the valves are opened. My first suggestion was: Harwire, through Digital I/O, . But there are too many signals to be interchanged. Edited 21 Sep 2005 by Mushu

[Mushu 0]

I have been talking with the company who programmed the Siemens PLC and they have a solution: Install a new S7-315-2DP with a Ethernet CP343-1 and a Profibus card in the Allen Bradley PLC. So the Allen Bradley PLC would communicate by PROFIBUS with the S7-315-2DP, and then this PLC would communicate with the Siemens PLC by Ethernet (there is not PROFIBUS port available). Do you know another solution????

[Mushu 0]

I have used RS232 to communicate Siemens PLC's with a Babel Box or with a particulas metter. It was not too difficult to create the protocol. Do you know if this could it be used with the Allen Bradley? Would it be dificult? Thanks.

[Wordman 0]

If you didn't want to upgrade to a 5/05, you could free up your RS232 port by using DH+ to connect to your SCADA? then you'd need a KTX card for the PC.

[gravitar 3]

When I worked for Mac & Mac and someone would call up with a communication dilemma like this, we'd tell 'em to call ProSoft. (www.prosoft-technology.com) A quick search of their website turned up this: http://www.prosoft-technology.com/content/.../view/full/5946 Which may or may not help you.. It is a card that fits in the SLC rack and communicates using the Siemens "3964R Protocol". Whatever the heck that is. And people tell me that DH+ and DH485 are cryptic names.. sheesh! Anyway, you might give their techies a call (or call Siemens tech support) to see how difficult it would be to make your Siemens PLC communicate using that protocol.

[JesperMP 2]

I wrote a whole lot in the Siemens section. As most replies are in this thread then I will add it here: There is no easy way. S7 and AB can NOT communicate directly with each other via Ethernet. 1. Install a CP341 with "loadable drivers" in the S7-300 rack. Siemens has a driver for the DF1 protocol that most (but not all) AB PLCs also use. You can then communicate natively between the two PLCs via DF1. (not possible for you because the serial port is allready used for Intouch). 2. Connect both PLCs to a PC, and then let the PC act as a middleman in the communication via OPC. You will need an RSLinx OEM license, a Simatic Softnet Ethernet license, and an OPC client that does the datatransfer between the two OPC servers. 3. Let Intouch be the middleware. I only recommend this if the connection between the S7 and AB PLCs are "not so critical". You can connect Intouch to the S7 PLC via its own driver. Then do the dataexchange in Intouch via a script. 4. If the datexchange is critical, and the timing is also critical then a radical and efficient way is to install a Profibus slave card in the SLC rack. SST (aka Woodhead) makes such cards for the SLC platform. The S7 must then have either onboard Profibus (S7-314C-2DP, or S7-315-2DP, or S7-317-2DP or S7-318), or there must be a Profibus card in the S7 rack (CP342-5). edit: 5. The soultion suggestedby gravitar will require that a CP341 is installed in the S7 rack. The CP341 can speak "3964R". 3964R is used a lot more on the old S5 platform. It will be relatively slow, and probably just as or more expensive than solution 4. Edited 22 Sep 2005 by JesperMP

[JesperMP 2]

Why is there no Profibus port on the S7 PLC that you want to connect to ? If it is because it is a model without an onboard DP port, then you can either exchange the CPU with one that has (for ex exchange a 314 with a 315-2DP) or install a CP342-5 in the rack. To use one more PLC as a gobetween in the middle is a real cludge if you ask me.

[Mushu 0]

Thank you to everybody. I am going to think about all your answers, and I will let you know what we decide. The Siemens PLC is a CPU 416. They have not told me if it is a CPU 416-2 or 3. I think that the company that it programme the Siemens does not want to change their PLC, so they don't want to communicate through PROFIBUS. They don't care how much cost to any third party. If it is a CPU 416-2, and both ports are used. I don't think there are used all the nodes (125). Do you know if there would be any problem to connect both PLC extending one of the PROFIBUS networks (of course, if there is not distance issue)?

[JesperMP 2]

Oh its an 416, and I was thinking it was an S7-300 the whole time. There is a risk that it is a 416-1. Then it only has an MPI port - no Profibus. If it is a 416-2 or 416-3 then it has at least one Profibus port. In that case you should certainly be able to connect it to your SLC via an SST Profibus slave module. The program of the 416 has to be modified in order for it to scan the new Profibus slave. So you have to coordinate it with the suppliers of the 416. Try to ask for the EXACT type number of the 416. How very arrogant of them. How do they then suggest to make interface signals ?

[Mushu 0]

I am receiveing the information piece by piece, so I am discovering new things along the investigation. At the beginning I though as well it was a S7-300. They prepared their PLC to communicate through Ethernet, but the Allen Bradley Ethernet protocol only works for Allen Bradley products, so their solution is not good for our PLC. I will let you know how this story finishes. Thank you.

[JesperMP 2]

It sounds like the other supplier has made a strategic decision that interface signals must pass via Ethernet. And because they have decided so, then they cannot change their minds now. It wouldnt happen to a german company ? For them to connect via Profibus would be a breeze.

[Mushu 0]

Thank you to eveybody. I have been in a commissioning for a while, so I could not answer earlier. Finally we lost the project. Don't ask me why, my boss, the customer, the customer's boss, third companies??? I don't know. As far as I know: the solution using a Siemens PLC as a bridge between the Allen Brandley PLC and the other Siemens PLC was to expensive, from the hardware point of view. The customer asked to convert the existing AB into a Siemens, so this would involve a higher cost in programming and test. I think the customer chose this solution. Thanks anyway.