GE fanuc 90-30 internal relay??

fhervrylesestoso · May 6, 2011

Experts!

GE Fanuc 9030
CPU374

is it possible to have an internal input?? i mean; for example,, %I01985,G is an input but this input (%I01985) is not wired on IC693MDL645... unlike other inputs such as proximity switches that are wired on the said module..

Thank you

Steve Bailey · May 6, 2011

Yes, you can do it, but why would you want to?

fhervrylesestoso · May 6, 2011

Just curious about what I saw here in our plant, Mr.Bob told me that this is configured on HMI. draw a button then assign an input.

Thank you very much!

Steve Bailey · May 7, 2011

I like to identify the variables I use as HMI buttons by including the letters "HMI" in the their name. I also tend to use %G addresses rather than unused %I addresses. That's simply personal preference, but since I don't use %G for anything else in the program, there is no confusion when I'm trying to troubleshoot. In your example, %I01985 is probably a good choice if your real machine inputs are low numbered %I addresses.

Tom Jenkins · May 7, 2011

Steve Bailey said:
In your example, %I01985 is probably a good choice if your real machine inputs are low numbered %I addresses.

I don't like doing this. Some one looking at the program is going to be searching for a pushbutton someplace. It also ties up an input you might want to use later for anothr function.

I really don't see any advantage to using an input address for an HMI function instead of using an internal coil. Many brands of PLC won't let you write to input addresses directly over the comm link at all.

tomalbright · May 7, 2011

And, hypothetically (I've seen it done!) GE will automagically configure your ethernet cards using IO addresses. I don't know why. But, it will use a block that may already be used elsewhere if it isn't specifically set up in a module location. You have to check these on installation, as this will surely Make Your Day.

There's a lot of addressing room preconfigured in the GE PLCs, and cramming everything together isn't needed, and doesn't save space. Use other addresses for HMI and you should be good to go.

nwboson · May 7, 2011

Wow. That's crazy talk there boys. Inputs should be inputs that you can measure with a meter. Boys should be boys. And goats should stay out in the fields where they belong. Principles to lead a good life... JMHO.

Steve Bailey · May 7, 2011

And, hypothetically (I've seen it done!) GE will automagically configure your ethernet cards using IO addresses. I don't know why.

Nothing magical about it. The ethernet module reports status information to the CPU and uses %I input points to do it. When you configure the module, if you don't specify the address, the software will pick the next available address and assign it to the module.

Tom Jenkins quoted me out of context. I'm personally not in favor of using %I input addresses for HMI buttons. When I'm troubleshooting a GE PLC I like to know for certain that a %I reference in a program means something associated with a module.

RussB · May 7, 2011

Steve Bailey said:
When I'm troubleshooting a GE PLC I like to know for certain that a %I reference in a program means something associated with a module.

This is a good idea. When choosing addresses for the HMI buttons keep in mind that some bits are always retentive (%G, %I) others are never retentive (%T) and some are selectable, (%M).
I seen one situation where a retentive bit was unknowingly used for a Momentary HMI (Jog) push button (maintain 'ON' while pushed) to move a slide. The PLC power was turned off while moving, and when power was restored there was unexpected motion. Even though the 'Jog' button was not pressed the jog bit remained high.

Tom Jenkins · May 7, 2011

Steve Bailey said:
Tom Jenkins quoted me out of context.

Sorry about that, Steve. Obviously I misunderstood your statement!

Steve Bailey · May 7, 2011

No problem Tom. My post was far short of a paragon of clarity.

tomalbright · May 7, 2011

Steve Bailey said:
Nothing magical about it. The ethernet module reports status information to the CPU and uses %I input points to do it. When you configure the module, if you don't specify the address, the software will pick the next available address and assign it to the module.

True, I saw this done while I was "new" to GE, and installing a 9030 in place of a 9070. We installed ethernet first, then IO modules. Trying to troubleshoot why our "I's" weren't working was very interesting.

GE fanuc 90-30 internal relay??

fhervrylesestoso

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