Modicon Programming Method


Thread Starter

Bryan Weir

At our site we use Allen Bradley PLC's almost exclusively. Our control infrastructure is wholly geared towards this. We do however, have one machine, which is quite critical to the operation and which uses a Modicon PLC. I have only recently assumed responsibility for this machine and when I made enquiries about its history I was surprised to find that we have no means of programming it or, for that matter, backing up the
program. This situation has arisen because it is a reasonably simple operation and the program never changes. It has however made me extremely nervous about the consequences of a major failure.

The processor, which is a few years old, has a part number - AS-M84A-002. Can anyone advise me on a cheap and cheerful method of programming this unit using a PC? Is there a cheap software package available which can be used? Obviously this does not have to be all singing, all dancing software. I only really need the ability to connect to the processor to upload and download and perhaps make minor modifications. Also, as an
Allen Bradley site I don't want to go making large investments in other manufacturers stuff.

Bryan Weir
Equipment Development Engineering
Polaroid UK. Ltd.

R A Peterson

IIRC, this unit programs with a handheld pendant and the only way to save the program is to a prom in the pendant. I'd be worried too.

Blunier, Mark

The Micro-84 has two ways to program them (that I know of). One is to use the hand held programmer, P370-001. The other way is to use a program pack. The program pack stores a copy of the PLCs program on a flash rom, so it is for backup only. The program pack can be used to restore a program by itself, but to save the program to a program pack, you'll need the programmer. My programmer crapped out, and my local guys said they couldn't get them anymore, but they would get a guy from another region to come down and retrieve the program for $400. Fortunately, by the time I got the PO cut, my local guys found a dusty programmer in their wharehouse, and gave it to me for the $400 I was going to spend on the service call.

Mark Blunier
Any opinions expressed in this message are not necessarily those of the

Rob Faragher

Check your number again. I've worked with a few Modicon products and that mumber comes up with nothing searching their site, nor have I ever
heard of it. there is an old series "884" which you should hope this is not as it does not support any convenient programming method - it uses tape based proprietary programming boxes.

984 is more current and is well supported by Modicon's Modbus programming software and much better ProWorx or NxT from Taylor, now owned by GE and I think licenced to Schneider.

From your number I would guess it is one of those as opposed to the later products Quantum and Momentum. Try the website - just type in

Good luck.

R A Peterson

I think the part number he has is for a micro84. an early shoebox type beast. i don't believe it ever had any programming software for it, only a
handheld pendant. IIRC, you could only store the program to a prom in the pendant. there was no other way of archiving it. from what i have heard
about this product, and my very limited experience using it, I am amazed it is still working. I think it was only available for a few years back in the mid 80s.

William L. Mostia, Jr

There is a US company that stocks old Modicon stuff and could possibly have
a programmer for your Modicon. They are:

3372 Smith Farm Road
Matthews, NC 28105
Contact: Scott Taylor, PLC Systems Specialist
e-mail: [email protected]


William(Bill) L. Mostia, Jr. PE
Principal Engineer
WLM Engineering Co
Independent I&E Consultant
P.O. Box 1129
Kemah, TX 77565 USA
E-Mail: [email protected]

These opinions are my own and are offered on the basis of Caveat Emptor.