Modifying a SLC 500 file to change an output address.

A customer asked if I could change an output address in a SLC 500 that he thinks is bad. I've not worked with that PLC before, so I asked him to send a picture of the programming port and any cables they might have. I'm scheduled to go there this morning, and he's an hour away, so I need to make sure I'm able to work with it. The first question... Does Logix 500 work with it? It just occurred to me it might be before that time. If Logix 500 works, are there any "gotchas" I should know about.

I'll do some searching, but since my time is short I wanted to throw this up first and see what comes of it.

That looks like a SLC fixed hardware style. Yes, RSLogix 500 supports it. The RJ45 socket is DH485 NOT Ethernet. It has 24vdc on one pin, so use the correct cable with it. If you don't have one, get one from Mark (even if you use their PIC today):

https://www.plccable.com/allen-bradley-1747-uic-usb-to-dh485/

You will probably have to jump through hoops to get the 1747-PIC to work if it is still possible at all. I recall giving up using those back around 2007. If your laptop has a real serial port, I'm saying there's still a chance.

Sell them a Micrologix 1400. You might have to include a wire stretcher. IIRC, the outputs are on top and inputs on bottom and I couldn't bring myself to mount a 1400 upside down the last time I made that migration, so I stretched 90% of the I/O wiring (replaced it).

Logix 500 is indeed the software you will want. Changing the output address should be reasonably straightforward, just use a cross-reference or find all to track down each instance of the bad output and change it to the new one.

Getting connected in the first place is likely to be the major hurdle.

The 1747-PIC pictured is obsolete. According to Rockwell literature it will only work with a built-in COM1 or COM2 serial port, and the driver was dropped from RSLinx some time ago and is unsupported since Windows XP or so. (Apologies if the details are not quite correct, I've never used one myself).

The modern replacement for the 1747-PIC is a 1747-UIC USB to DH485 adapter.

Wow... there's always that moment where you wonder if you should come here to ask, or just dig it up online. Again, I'm glad I asked.

I don't have Paul's adaptor, I've got Tim's (Wilborne). But I try to support both of them. I'll focus on that adaptor and leave my curiosity of the old 1747-PIC out of it.

Thanks, guys!

I still have two PIC boxes waiting for the Smithsonian to call.

77nomad said:

I still have two PIC boxes waiting for the Smithsonian to call.

Click to expand...

Haha! That's funny! I see some old, old stuff, for sure.

Follow up, after the service call: The problem wasn't the outputs. I pulled up the ladder and found his issue was 2 intermittent limit switches that needed replacement. ...that's NEVER happened before, has it?

I had so many problems with the PIC back in RSLogix ver 2.8 & 3 days that my mind blocked them and forgot all about them.


Now if all those memories of the crack head ex every go away..........