Andy S

Simply because Siemens ALSO markets a DCU that interfaces to the GE Logicmaster/Koyo PLCs, which they also sold. I use a Siemens DCU on a Logicmaster One; it actually works pretty well. If your DCU doesn't use pins 14-17, fine; no need to get testy...

If you have one of the first Logicmasters, Logicmaster 1 won't let you monitor the PLC while it is running - I found this out the hard way. I think for the later Logicmaster 1 FAMILY software that you can. The function keys for online monitor are just missing in the older version (you get all of them when you order Logicmaster 1 from the people at Qualitrol/Cimtec, 3 3.5 inch floppies and 5 5.25 ones - they're both the same software. Tells you how old it really is...). Steve, does the keypad programmer actually tell you the states of the logic? I hadn't figured out how to tell; I just scrolled through to write down all the mnemonics in my program before I got LM1. But it would certainly have given me a bit of an edge on one recent troubleshooting trip when I DID need to monitor logic.

I think Cimtec and Qualitrol are the same people; I went to Qualitrol.com. I'm not sure why they quoted you a higher price; may be that I ordered the software through my company; LM1 cost $100 and a pre-built virtual hard drive to run it under DOS was $200. Basically it was the ONLY way in to a controller out in the field that I needed to update - no longer supported by anybody. Steve has a point - if the supplier is doing updates at a reasonable cost, it may be worth it to let HIM have the responsibility to keep it running.. But there are some service companies out there that charge on the order of $1000/day on a project; I'd be sorely tempted to try and "roll my own" for that, especially if you have all the hardware (DCU, RS422/232 converter, cables to the DCU...). Just the other day I saw a Siemens TI305-02DM DCU for sale online for $235 (I forget where; can always Google it); I have one of them, and it lets me get into all the models of GE Logicmaster from 101 up. I haven't tried on the other Koyo knockoffs, but it should be similar. Had to make a cable for the RS-422 on the DCU (when did Radio Shack stop selling DB-25 connectors?) to run to my RS-422/232 converter from B&B Electronics.

Qualitrol/Cimtec (800-784-9385) is the licensed supporter of GE Logicmaster 1 products and software; they will sell you a copy of Logicmaster 1 including all of the families (L1, L1 family, jr,...) on 3.5 and 5.25 disks, and a manual (can't find one from G.E.) for $100. They also will sell you a CD with an image that will run DOS to run Logicmaster under XP/Vista/etc. using Microsoft Virtual PC. It works pretty good, and you can get to the serial port and communicate. Their CD is about $200, but it can be a pain setting up VPC on your own. I think the price is worth the hassle; their CD is turnkey. They also have various hardware, but not especially cheap; you can find a DCU online from a few places for about $250, and an RS-232/RS-422 converter for about $75. Gotta make your own cable for it, though...