Proficy Machine Edition

Hello Experts
It may sound simple for you experts. I have to add negative transition contact in the ladder logic and for some reason this instruction is not happening. I am new to GE programming but I had done in Siemens few times by simply drag and drop in the ladder circuit. I can do PLC programming but never done in GE fanuc. Just wondering am I missing something obvious before executing the negative transition contact instruction.
Any help will be really appreciated.

Regards
Manoj

Some GE-IP PLCs do not allow transition contacts. If you are programming a 90-30 or Versamax, you can not use a transition contact.

You will have to program a transition coil and then use a normal contact from that coil. Both will have the same address.

Thanks for Quick response and your Idea is working perfect.
Now the second question is if I have to define a memory bit to that Transition contact, then how would I know which memory space/area is available. Comparing with Siemens, you can look into the Assignment list and use the memory bit which is not been used. But like I said being new to GE, I Don't know where all these instructions (may be with different name) are sitting in PME.

Regards
Manoj

Internal memory bits are %M bits. Bits are listed in Variable List. If you aren't sure, you can search for the bit you want to use.
By default, the software will report "duplicate coil" when you create an output if the address was already used.

One issue with Proficy - If you forget the percent symbol, it will create a name, then demand an address for it. Annoying.
Let's say you choose a coil, and want to name it %M0. A shortcut is to type the number first. "0M" will automatically add the percent symbol, and create "%M00001".

If you don't know (or care)which %M bit to enter, when prompted for the address, type %M ans hit enter; Proficy will insert the next available address (at the upper end of the used addresses; it will not fill in holes). It will do this for other memory types as well (ex. %R).

Thanks Mark.. You hit the right spot....
Many Thanks

If you go to the Navigator Window, "Options | Controller | Hardware Configuration" and change the parameter "New Reference Assignment" to 'First Available' this can be somewhat controlled.

If set to Next Available (default), new reference assignments are made from the next highest available reference memory location.
If set to First Available, the editor attempts to assign reference memory from the first unassigned fragment that can accommodate the required new assignment length.


On a VersaMax Nano, the Next Available option is always used even if you select First Available.

Click to expand...

Thanks, Russ... something I always wondered about but never got an answer to.