GE bit addressing

I have an AB SLC500 program that I need to convert to a GE Fanuc 90-30 program. Right now I just have LM90 but should be receiving my copy of proficy ME any day.

My question is this: is it possible with GE to address a bit in the ladder logic from an integer word (%R) or do I just have to use bit registers (%M). For example, in my AB logic I use N9:20 as a message file and I use bits N9:20/0 thru N9:20/15 as individual messages in that file. Maybe there's a different method to do this with GE that I'm unaware of as well?

Hopefully the information I've provided is clear enough to get us started.

Thanks,
Steven

Hello,

I am not a GE expert.

I just scanned through all the docs on GE I have and none of the docs had a bit reference for %R.


Good luck,

Mark
http://www.peakhmi.com/

GE 90-30 doesn't let you address %R memory to the bit level, but it does let you copy a %R address to a %M address. When you do that the %M address must be on a byte boundary (%M81 or %M89 for example). Use the MOV_WORD instruction. It will copy all 16 bits of the %R word to 16 consecutive %M addresses with the one you specify corresponding to bit 0 of the %R word.

In your example, if %R920 was your GE equivalent of the AB N9:20, then use a MOV_WORD instruction with %R920 as the source and %M113 (for example) as the destination. %M113 will correspond to bit 0 of %R920 (N9:20/0), %M114 to bit 1 (N9:20/1), ..., %M128 to bit 15 (N9:20/15).

Great, that's what I was looking for. Thanks for the replies.

If there is no Genius network involved, I like to use %G bits for this kind of data, where one may need to use it as a "WORD" or a "BOOLEAN". There are 1280 of them and if you address the words on byte boundaries as Steve indicated one can do math, masks, or other "WORD" function plus each individual Bit address can be used as a contact or coil. The only thing one needs to keep in mind is that they are always retentive, for data, that can be a plus, although they may be "cleared" whenever needed.

Well sure there is: BIT_TEST_WORD

But I wouldn't do it with this instruction. As others have said, I'd move my register to M, T, or G memory and then have access to the bits directly.

Hey Paul,
That is correct and there is a "BIT_SET_" function to go with it. They work fine but should be used sparingly as they are very inefficient in that they add a lot of time to the scan. Plus they make logic difficult to follow and troubleshoot, mostly because of the restriction of no contacts allowed between a function block and a coil.

Thanks for all the guidance.

Trying to convert this program with LM90 is wearing me out. Hopefully things will go much smoother when my prophecy software gets here.

You should talk to your supplier and get a demo CD of Proficy ME. It will run for 4 days without restriction and you can call 800-433-2685 to get that extended to 30 days.
Bottom line is, you should not have to wait to use this software.

I finally got in touch with the right people this morning and my demo should be shipped out today. I thought the numerous phone calls asking about the status of my order would have alerted them to the urgency of the matter but it wasn't until I mentioned the word "demo" that something clicked. After that, it literally took two minutes.

That's good news on the Proficy software.

I will warn you that it is not the easiest software to use at first. I had used LM90 for years and was very proficient. I also programmed with AB and Siemens before trying Proficy. I pulled my hair out for a few days before a GE rep came and showed me a few things that made life easier. That was back in version 4 and I've been using Proficy ever since. It is now one of my favorite programming packages - I really like this software!

Things that made life easier for me:
1. Window - Apply Theme - Logic Developer PLC. This will "fix" issues with some windows not being displayed. You need all your windows so you can get things done.

2. Once you have a program open, be sure the "Feedback Zone" window is present and notice the tabs at the bottom of this window. Use the "references" tab when clicking on logic to see the cross-reference for a variable.

3. The "Navigator" window has tabs on it. Familiarize yourself with all of them. On the first tab there are settings for how the software works. Under Controller General I always turn off Multiple Coil Use warnings, etc.

4. The "Companion" window provides help on anything and everything.

5. Variables or tags are managed via a tab on the Navigator window. Create filters so you can sort by Inputs, Outputs, M-bits, T-bits, G-bits, Registers, etc. This will make life easier. Another thing I do is manage all variables in an Excel workbook - I never use the Variable editor at all. I do everything in Excel and then import to Proficy. This is a huge leap forward in productivity.

6. Anywhere in ladder you can drag & drop and move things any which way you want with your mouse.

7. Type an instruction and you will quickly become very fast at entering logic. Type NOCON NCCON COIL to get normally open, normally closed, and a coil. If you are not sure of what to type, just type the first letter and the software will pop up a list.

I hope this will encourage you. If you have questions about how to do things there are some video tutorials on the second disc of the software and please - ask questions here.