HMI/Multiple PLC's?

[JasonTheSparky]

Hello all! I'm fairly new to PLC programming and even newer to this site, so please be kind! The answer to my question might be right under my nose, and if I don't see it I apologize. Anyway-

I have a SLC 5/03 rack in a machine communicating with a PVP 1000 at my plant. My goal is to add an additional input (a photo eye probably) way on the other side of my plant, but I need to do it very inexpensively. I would like to utilize my plants network to cover the distance, but without purchasing additional hardware, like a Flex I/O for instance. I do have an unused Micrologix 1100 sitting on the shelf. Is it possible to network my PVP with my SLC and a ML? Or possibly have the ML send its data to the SLC? I know that's possible with tags in the 5000 series of controllers, but not sure with the 500's...

I'm still learning all of the capabilities of each, and I thought it might be quicker to ask the brain trust and maybe get some other clever ideas in the process. Thanks guys!

 

[ASF]

Welcome to the forum!

Any of your suggested ideas are in theory workable, although there's a few things to check before deciding which is your best option.

As the SLC5/03 doesn't have ethernet, I'm guessing that it'll be communicating with the PVP over serial. It's possible that there's an ethernet adaptor there, but I'd suspect the link to the PVP would be serial. Is this the case?

So if you wire your sensor into the ML1100, and connect the ML1100 to the network, then yes, a PVP on ethernet can read the ML1100 over ethernet. But. Only if your PVP is also on the ethernet network! If it's not, you could always add it to the ethernet network and it can talk serial to the SLC and ethernet to the ML1100 at the same time, provided your PVP does have an ethernet port.

The ML1100 can also talk direct to the SLC, so you could do it that way - but again, you need to check network connectivity. Is your SLC connected to the Ethernet network? Again, the 5/03 doesn't have ethernet, so I think you'd need something like a NET-ENI module for it to be connected in.

 

[JasonTheSparky]

TYPO! My mistake... my controller is a SLC 5/05. The controller communicates to my PVP via Ethernet/IP, both being run through an unmanaged switch, which is also connected to the plant network; hence my desire to utilize it. My question was whether it is possible for the PVP to talk to 2 different PLCs via Ethernet/IP or not. I would only be using a single input on the ML, and the PVP throwing up a simple display message to the operator under a condition sensed by my (possible) photoeye.

Sorry for the mis-information!

 

[Hundikoer]

TYPO! My mistake... my controller is a SLC 5/05. The controller communicates to my PVP via Ethernet/IP, both being run through an unmanaged switch, which is also connected to the plant network; hence my desire to utilize it. My question was whether it is possible for the PVP to talk to 2 different PLCs via Ethernet/IP or not. I would only be using a single input on the ML, and the PVP throwing up a simple display message to the operator under a condition sensed by my (possible) photoeye.

Sorry for the mis-information!

Yes, depending on PVP version/type
http://www.plctalk.net/qanda/showpost.php?p=657787&postcount=4

 

[ASF]

Ah, yes, that does make a difference! Yes, in general a PVP can talk to multiple screens - I'm not sure if there is a hard limit or just a point at which you should step back and ask yourself why you're doing this to yourself - but talking to two PLC's at once is dead simple. You just add the second PLC to the RSLinx Enterprise configuration and assign it to a shortcut. There are some PanelView models that are restricted to communicating with one controller - someone else posted a list earlier so let me just take credit for their hard work and drop the list in here:

The standard PanelView+, PanelView+6, Panelview+7 Performance can talk to multiple processors. The Panelview+ Compact and new Panelview+ 7 Standard are limited to 1 communcation with 1 processor only.

You should be OK with a PVP 1000, but just for your information

As to whether you should get the HMI to read directly from the ML1100, or transfer to to the SLC and have it get the info from there - to me it would come down to, would the SLC ever have need to know about that condition? Is that sensor related to the SLC system? Or are you just using the existing HMI to show some information about an unrelated piece of plant?

If the sensor is related to the SLC at all, I'd be inclined to send the data from the ML to the SLC and then have the PVP read it from there. If it's relevant to the SLC's process, it makes sense that the SLC knows about it as well, and then your PVP is getting it from the main data source, which makes sense and is easy to follow for diagnostics, troubleshooting, or further modifications.

But if the sensor is completely unrelated to the SLC and the SLC will never need to know about it, then I'd just have the PVP read the ML1100. Again your data sources make sense - you're showing SLC system data from the SLC, and [random other system] data from [random other system]'s PLC.

In any case, both options will work!

[edit] there is of course the disclaimer that you'll need to be able to have all three devices on the same ethernet subnet, or have routing between subnets, etc etc, but by the sound of it that part is all under control.

 

[Saffa]

Personally, I'd use a MSG instruction in the SLC to poll data in the ML and then read it from the SLC using the panelview. That way if you need to use the photo-eye for a control purpose, or if something needs to be added to the ML in the future that is used for control by your SLC, then the work is already done. But reading directly from the ML will also work.

 

[ASF]

Another thought - if there's an existing AB PLC over there already, you could ditch the ML1100 altogether and just wire the sensor into that one...

 

[JesperMP]

I am guessing you intend to reach to the ML1100 via an existing plant network, to save money.
If so, you need to talk to the local IT guys. It may be a question of getting IP addresses coordinated. Maybe you may have to accept to adapt IP addresses in the existing hardware. Maybe you need to bring cake to the meeting with the IT guys

edit: Just this. If the single photo eye is really important to your application, IMO you should not mix your network with the general company network. If the functionality of the photo eye is a nice-to-have, then OK.