Micro 84

We are utilizing a Gould Micro84 controller set to operate our Tertiary treatment sand fiter backwashes and they are dead -- they were installed in 1984 with B351 input and B350 Outputs -- at this time, I am looking for units to replace these -- (it seems that we need to get the information to replace these first) I need imput that these units are now basically obsolete - - we are looking into new scada upgradable PLC's -- like a TESCO or ????? any info on the existine Gould Micro 84's is very much welcome
thanks in advance

If I remember right, Modicon put the Micro84 to sleep in the late 80's or early 90's. You might contact your local Telemecanique rep - they now have the Modicon line.

I don't know what the TESCO is, but ANY modern, entry-level plc on the market today has much more power than the Micro84 ever dreamed of having. What other PLCs do you have in your plant today? You might check into the AB CompactLogix or perhaps something from AutomationDirect. All very capable.

well -- we have different types of mostly obsolete plc's -- TESCO is of course another manufacturer which have units installed in our park for ww as well as water com's -- we are a 1mgd plant and as of this time in our history, are finding that so much of our equipment is becoming more and more out -of-date!!!
so I am attempting to get info on our existing panel controllers and dont seem to find much other than companies that rebuild units
My boss asked me to see what I can come up with to justify replacement !! LOL
(typical Gov work!!!)
since we are now working in crisis management mode! its nice to get feedback on such obsolete equipment -- and thanks for the note!
Joe

The micro 84 is dead as the dodo, but it's legacy lives on. Control MicroSystems makes a very nice RTU that programs in ladder logic similar to the 84. The Modicon Momentum product line also uses similar ladder logic, but the Modicon (Telemechanique/Square D) software is a bit pricey.

If you have access to the original programming you may want to consider staying with the modicon or modicon clone PLCs. Modicon had a unique scan structure (top to bottom and THEN right to left by columns) that may make it difficult to directly convert the logic to a different PLC platform. On the other hand if you have to write the program from scratch then, as Ozee says any PLC will do the job.

Thanks Tom -- I am just trying to put something together for justification (READ -- BUDGET!!!)
I believe thet a new program is going to be written for ops so what we are doing is getting our ducks in a row now so that we can put in a solid reason to replace these units -- all that I have been reading up is that yes, they are no longer being produced and that there is a much more efficient animal out there
we are in constant monitoring mode especially after slight power bumps (this is what knocked out the gould units finally)
so now we are running a backwash manually and even though we get thru all we need to in automatic mode, we do need to come up to the 21st century!!!
but its the bigger side of things (read: higherarchy!) that needs that extra nudge !!! LOL
Thanks again members -- I did not think that a site like this existed !!!
Joe

Please understand that I know absolutely nothing about your process, but let me ask a couple of questions to help direct you in a pattern of thought as you seek financial justification for this conversion:

1. Is there a risk involved in running the backwash manually? I.e., human safety, mechanical, chemical, getting distracted during the process, ...

2. Are any hazards created by performing the backwash manually? I.e., accidentally missing or repeating a step, accidental chemical release, ...

3. Are there any efficiency gains that could be obtained through automation? I.e., operator efficiency (can we reduce an operator whose only job is to run this manual process, or can he multi-task better), reduced chemical/component usage, ...

4. Are there any quality improvements that could be obtained through automation?

5. When (not if) that Micro 84 finally lays down and dies, what risks will that pose? How long will it take you to get back up and running?

6. How much have you been spending in the recent past on repairs? Forecast for the future?


Financial justification for replacing an obsolete PLC is a very difficult task. Alot of the bean counters only see benefit if the project will save money or create income. Many times, they don't understand (though they say they do... but that's a different story) the need to make continued investment in automation. They allow mechanical components to be replaced as they wear out, but not control...

Right now, your system is running, albeit not as well as you would like. I don't know -- will this upgrade help you make your product faster, cheaper, better? Those questions above will help determine that. If it won't, then your sales job to management becomes more difficult - and you have to convince them, not of a cost improvement, but of a cost avoidance. (questions 5 and 6) There truly is a cost associated with obsolesence. Our jobs are to define that cost and come up with reasonable means of offsetting those costs with control system upgrades.

Hope this helps. Good luck!

OZEE -- THANKS SO MUCH FOR THE RESPONCE --
IN ANSWERS TO YOUR QUERY --
1. - Not much risk is involved to an operator however, there is some mechanical, and distrating is always a possibility, the main issue is man-time involved and weekend coverage is also a big issue -- this is why full automation is desired.
2. -- the issue again, backwashing does involve flow to a lift station and the possibility of flooding the station will through a call-out alarm (hence the weekend coverage issue again!)
3. simply put, with this section of our plant in automatic mode, again the man hour question comes into play -- while in winter our flows are down, we still have the other basic issues to deal with.. IE. freeze problems,broken water lines etc (higher elevation,sierra mountain range etc)
4. well -- this is neat!! we are and have been running so much equipment that has been in operation since 1975 - upgrades in 1983 and the last one in 1996, the unit has been in use since the early 1980's and we (I) have just gone through the old units that were on the shelf (used and like most, left there not working)
so upgrades to a more modern unit is desirable also due to the power issue - we have momentary bumps in the winter and the last one as I stated, killed the unit, even trying to reboot has not worked. LOL and I just rebuilt a pump that has not been in operation in 15 years!
5. this is easy -- I work for the FEDS ..... think about it !!!
6. I have been here for a year now -- so - see question 5 above....they like what I do because I like what I do!! LOL
all kidding aside, I have been attempting to utilize more of the equipment that I see here that has not been in operation for so long because I hate to see wasted space,and equipment that could be perfectly good to use but due to changes in this plant, are no longer being utilized -- it's something..... the Gov needs to have a fire sale once in a while... this way maybe we would not need this conversation -- they would not have to ask for the reason why -- just why not!
thanks Oz --
Joe