Need help on a beginner; programming 2 controllers to share I/O

metalsiren · Jul 17, 2007

I have 2 CompactLogix 1769-L32E controllers. Each one has the following modules:

Slot 1: 1769-IA16 AC Digital Input
Slot 2: 1769-IQ16 DC Digital Input
Slot 3: 1769-OF4CI Current Output
Slot 4: 1769- OF4VI Voltage Output
Slot 5: 1769-IF8 Analog Input
Slot 6: 1769-OW16 Digital Relay Output
Slot 7: 1769-OW16 Digital Relay Output

I have them connected through Ethernet. I am using RSLogix5000. I have been reading 1756-pm001_-en-p.pdf but I am getting confused and overwhelmed.

Once I open the program, I can add 1769-L32E controller; how do I add the other 1769-L32E controller?

In the I/O configuration, how can I have the 2 controllers and their I/O modules showing?

Do I need a seperate routine for each controller?

As for programming, example, how can I program an Input XIC (Examine On) from one PLC to turn on a digital relay output on the other PLC? Like:

PLC 1 Input . . . . . . . . . . . . . . PLC 2 Output
--] [--------------------------------------( )--------

also,

how can I move, using the MOV function, a current looping in an Analog input of one PLC to output the same 4-20mA current out the other PLC?

It seems I need to use produce and consume tags, but I still do not know who to configure them.

I know it's alot, but I need all the help I can get as I am on a time crunch for this project. If I am dealing with only one controller, then I would have no problems. However, this project of communicating 2 controllers and their I/O modules is giving pain in the rear end.

Thanks in advance!

OZEE · Jul 17, 2007

Why two CPUs using the same IO??

Sounds more like you want redundancy -- for the you're going to want ControlLogix, not CompactLogix. Produced/Consumed tags isn't redundancy.

Outputs can only be owned by one CPU, so you'll have to define the output owners. The "other processor" can then request the "owner processor" to turn on an output, but it can't turn it on directly. If the owner processor is dead or the network is down, the "other" can't do anything about it.

I guess we need an answer to "Why?" or "What are you trying to achieve?" before we can give you a good answer to "How?"

metalsiren · Jul 17, 2007

I have 2 racks. With each rack I have:

Slot 0: CompactLogix 1769-L32E controller
Slot 1: 1769-IA16 AC Digital Input
Slot 2: 1769-IQ16 DC Digital Input
Slot 3: 1769-OF4CI Current Output
Slot 4: 1769- OF4VI Voltage Output
Slot 5: 1769-IF8 Analog Input
Slot 6: 1769-OW16 Digital Relay Output
Slot 7: 1769-OW16 Digital Relay Output

Each PLC rack is separated hundreds of feet away from each other. I have both of them connected through fiber through Ethernet converter in an Ethernet network hub/switch. My laptop is also connected to the network. I already set the IP address, etc, and I can see both controllers in RSLinxs.

An example of what I want is when an input in 1769-IA16 of one of the PLC rack closes or turns on, an relay output in 1769-OW16 of the PLC rack hundreds away close or energize.

rsdoran · Jul 17, 2007

Why not use Flex I/O or something if you want direct control http://www.ab.com/en/epub/catalogs/12762/2181376/104830/2746667/tab3.htmlAs mentioned you may be using Ethernet IP which may require some reading etc. www.odva.org and http://www.ab.com/networks/site-index.html

kamenges · Jul 17, 2007

As Ozee said, only one processor can truly control a given output card. If you want a condition from one processor to turn on an output in another processor you will need to write logic in both to make that happen. I would personally use produced/consumed tags to send the information. But you still need logic on both sides to route the command.

Keith

MartB · Jul 17, 2007

metalsiren said:
I have 2 racks. With each rack I have:

Slot 0: CompactLogix 1769-L32E controller
Slot 1: 1769-IA16 AC Digital Input
Slot 2: 1769-IQ16 DC Digital Input
Slot 3: 1769-OF4CI Current Output
Slot 4: 1769- OF4VI Voltage Output
Slot 5: 1769-IF8 Analog Input
Slot 6: 1769-OW16 Digital Relay Output
Slot 7: 1769-OW16 Digital Relay Output

Each PLC rack is separated hundreds of feet away from each other. I have both of them connected through fiber through Ethernet converter in an Ethernet network hub/switch. My laptop is also connected to the network. I already set the IP address, etc, and I can see both controllers in RSLinxs.

An example of what I want is when an input in 1769-IA16 of one of the PLC rack closes or turns on, an relay output in 1769-OW16 of the PLC rack hundreds away close or energize.

You can communicate between the two controllers using produced and consumed tags.
Each controller has it's own dedicated I/O, you cannot directly command one I/O card from two controllers.

I would suggest you read up on produced and consumed tags and then get come back and ask more questions if you have any.

metalsiren · Jul 17, 2007

Thanks, guys! Yeah, I see now that I need 2 separate RSLogix5000 programs, with each one to have its own ladder logic.

Now, I am programming an output (BOOL) to be a internal variable producer, but it says:

Failed to create a new tag.
Tag of this data type cannot produce data.

I guess it needs to be a DINT. But I only want a Boolean 1 or 0 value to be an output of the other processor as a consumer tag.

DBLD99 · Jul 17, 2007

Create a UDT and Produce and Consume the UDT, you can put as many Bools into the UDT as you want. The UDT needs to be in both processors.

Your not going to want to produce a lot of single tags it will clog up the network.

PeterW · Jul 17, 2007

Once you have created the DINT, you can then access each bit individually and also give them a description which means something.

You could also create a BOOL that is aliased to one of the DINT bits.

metalsiren · Jul 18, 2007

In one program, I added a DINT produced tag. I made a simple rung where a local XIC will turn on one of the bool value of the produced tag. I downloaded that to one of the controllers.

I created a new controller, and I am trying to add/retrieve the consumed tag from the previous controller. In the Consumed Tag Connection window, there are no controllers showing in the Producer pull-down menu. What am I missing?

PeterW · Jul 18, 2007

You have to set up the route in the I/O config.

Go to the control net card in the consumer PLC I/O. Then right click and select new module and select the same cnet card in the producer. Fill in its node address, slot and rack size.

From the new cnet card, right click and select new module again, this time it has to be the producing CPU, so it needs the slot its in.

The name you give it will then appear when you create a consumed tag.

metalsiren · Jul 18, 2007

Thanks a bunch! It works!

Need help on a beginner; programming 2 controllers to share I/O

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