Miprom 21 Fault 27 help

Hello all,
I am new to the forum and looking for help with this one. I have a Miprom 21 that keeps giving me a 27 fault when running on inspection. Fault 27 is a performance comparator trip. I have done all the recommended troubleshooting items in the books I can find but I cannot get this car to run properly. On inspection the car will not run unless I disconnect the wiring to the position encoder on the governor. If I leave it connected the car will only run about 18" and fault in either direction. It will recover and try to run again but only about 18". With the position encoder disconnected the car will run up and down the hoist way all day long without fault on inspection. In one manual I found a note that said the car WILL run on inspection with a defective or missing position encoder but this one will only do it if it's missing or disconnected. New motor encoder, new governor encoder, new MSU board, new relay pilot board and ribbon cable from pilot board to MSU board! I have tried changing combinations of channels on the encoder ie. A+ / A- or B+ / B- and nothing I have tried makes a difference. I'm sure I'm leaving some things out that I have done but this has been eating my lunch for a while now and I'm looking for some HELP!! Thanks.

How does it act on automatic? Same 18” then stop? What kind of drive?

I've had problems with the black connector at bottom of the relay pilot board, where the encoder signals come in. Usually I can do a good reseat, but I have had to solder in a newer style connector.

Make sure the Brake is picking. Also what does the error log say when running on automatic. Can also be caused by the car top encoder. Is this a Gearless Machine?

Hi guys. Thanks for your responses.

Indirtwetrust, it did act the same on automatic but i can't try it now as the floor table is gone. The drive is an Allen Bradley 1395 DDC.

Jcjmowery, the new relay pilot board has the new green Phoenix connectors on it.

john jay, the brake is working correctly. can't run on auto. This has a governor encoder instead of the car top encoder. it is a geared basement traction machine.

Does it run long enough to compare the speeds on the Motion Info screen? If motor Encoder speed doesn’t match command speed there may be a drive parameter wrong. Check drive parameters 558 and 609. 12” gov should be 240 ppr, 16” should be 320. Did you do the velocity command adjustment when you put in the new MSU? I think there is a motor RPM adjustment in Motion adjust and make sure Jog is 100.

The lower you set I DRV VEL the longer you will have to compare the speeds before it faults.

Indirtwetrust, i have tried to check screen #3 in Motion info but I don't know how accurate it is. The tool is very slow to process the info. i took a picture of the tool but for some reason I can't attach it. I had Vcmd 47, Vfb 44 & Venc 8. I don't recall checking those params, I will do so. I could not find any info on any adjustment to the MSU board or any of it's pots so no to the velocity command adjustment. Do you the the procedure? Can I get a copy? We do have the correct PPR for the gov. encoder. I will check I DRV VEL and lower it. Thanks much.

Try these, set Min Overspeed Band to maximum. Raise KP Velocity by 10% and see if it runs longer. Check that the PPR in the Drive parameters, and PPR in the MSU are the same. Check that Brake Pick time is longer than Brake Econ time. If this is an analog drive and someone pulled the Main Line switch before shutting down the Miprom, you may have lost all the field programable parameters. Things like the floor table and motor rpm, if this happened you need to check them all.

Here's a pic of the tool.

john jay, I will look for Min Overspeed Band and KP Velocity, I don't recall seeing those before. I have verified the PPR settings. I will try the Brake Pick and Brake Econ settings as well. This is a 1395 Digital drive. I have checked almost every parameter against the job parameter sheets and the car next to this one. I haven't had to reprogram much, maybe 2-3 parameters.

Also check the Timer relays SB1 and P2, one should be around .25 longer than the other. I can't remember for sure which is longer, so if you have another running car you should compare it.

Wow, I’ll trade you a manual for that Kone tool! 😉
Those speeds are way off, is the car moving 50 or 8 fpm before faulting?

You’re sure the PPR is right in Motion Adjust? Could the gov encoder coupling be slipping? Is the Encoder voltage right? What about AC ripple?

Indirtwetrust, Sorry the tool belongs to the customer, government job. It looks like the car is accelerating to about 50 FPM. I don't know if the processor in the tool is able to sample the information fast enough and display it correctly in that short amount of time? Let's say that the Venc the is only 8 FPM according to the controller and I have changed the encoder, relay pilot board, MSU and ribbon cable. I have verified the feedback from the encoder is good with a scope. channels lead and follow each other correctly on a 12 volt scale. I recently swapped the MSU with another running car in the building and it ran another car in inspection with out fault. What am I missing? Do you have the info on adjusting the MSU pots?

Yes, triple checked the PPR on the encoder, New encoder coupling. 12VDC at the encoder and approx 11.9VDC back to the controller on the square wave on the scope. There was noise on the channels coming back but we wired in a BEI filter module in at the controller.

I’m just guessing here now but could the CPU be envolved in reading the Encoder feedback? Have you tried swapping CPUs?

Have you checked over the M switch. A bad aux. contactact can throw a 27 error. What is the error in the Drive Log?

Swapped the CPU also, no change.

Have not checked the aux M contacts as it will run without fault with the gov encoder disconnected. It doesn't log a drive error.

Any chance the tension sheave on the governor rope is bottomed out? How did this start? you say you have no floor table, so something must have happened to lose that.

Tail sheave looks ok, did not see anything there to indicate any slippage for the governor. the call came in with this same symptom. I believe the floor table got lost with all the swapping around of boards and parts off and on of power countless times.

I looked back through my old notes, I had a Mod throwing 27 error's because I didn't have enough field currant. Try checking out the field parameters, and bump up the field parameter. While your at it check out motor for connections, brushes and and such.

Did you swap the CN6 cable to the CPU? Another quick easy check.

I have not checked the motor field parameters. I will do that and compare to the other car. I did meg the armature and fields for integrity. I did swap the CN6 ribbon cable when we swapped the MSU board.

What if you just try to scale it in at inspect speed with the PPR adjustment in Motion Adjust. Not that it’s a real fix but it would be interesting to see if it would run consistently. Maybe you could even get it to take a scan. And if would run with MVEL over 150 fpm you could see if the 150 fpm ETS sensor board is reading the speed from the Encoder correctly.

I hadn't thought of trying that. I will give it a shot.

At this point I would try swapping the Motion Adapter Bd. They are plug and play. Also have you tried a reinit? It will tell you if one of the drive parameters is mismatched with the Miprom parameters.

Is the new governor encoder the same rpm rating?
What does the Debug Screen show under Motion Excuses while the unit is faulted?
Dragging/sluggish brake (already mentioned) will cause a 27.
Flakey brake switch (if used) will generate a 27/26 fault.
Bad contacts, broken wires at Brake relays (SB, SB2 I think).

Faulty Brake Pick issues typically appear in Motion Region 2 or 3.

make sure motor encoder rpm is set to encoder rpm under msu adjust motion adjust. this is one parameter that is not listed in the miprom 21 black book, but i have had this a couple of times. have had a couple cars that will only change this parameter if the power goes out, or if you do not shut down the switches before main line. motor encoder not position encoder.

Good morning all. I can finally breathe a sigh of relief! We had success yesterday!!! Here's what happened.

Bottomed out I_DRV_VEL to lowest setting of 30 FPM and car ran in one direction without fault. I could then get a better reading on screen 3 in Motion info to compare the Vcmd, Vfb & Venc. car was still reading about 7 FPM higher on Venc = 34 compared to Vcmd.= 27. Compared to another car running same I_DRV_VEL speeds were only 1-2 FPM different.

Thanks to all of your suggestions I began looking at motor parameters, specifically the PPR of the motor encoder, which was set correctly according to the job parameter sheets, and param 558 ME Base Speed. I first tried changing the encoder PPR param 609 higher and lower but it didn't seem to have much affect. Granted I didn' make extreme changes as I didn't want to set the car on the safeties if I could help it. So I changed it back and lowered ME Base Speed from 850 to 700 and the car ran up and down on inspection without fault! I gradually brought the RPM higher until it faulted again and left it in a happy medium at 750. At that point we were able to get a floor table scan and run the car on automatic for the first time in a long time.

Here's where it gets even more interesting. On automatic the car was running in the high 370's with a M_VEL set at 350 and yes just clipping the over speed switch on the governor. Dropped M_VEL down to 325 and car still running high 350's. Dropped M_VEL to 300 car is running in the mid to high 330's. The other thing I notice is that the car seems to be overshooting the pattern a bit, not really noticeable in the car but you can hear it in the machine.

Put the car on a heat run, top to bottom for an hour or so to get things warmed up. Car ran fine, not overshooting floors or logging any faults. For now I am happy the car is running but I would like to get to the bottom of why I had to make those changes! My gut is telling me that even though the encoder tag says 2048 on the motor and 240 on the governor there is some difference between them and the original ones! I could probably make some more adjustments to param 609 and maybe get the car running a little better but not going to mess with it for now.

Anyone have any thoughts on this? I REALLY appreciate all the help and suggestions along the way.

ADC Scale 1 is usually set at 2.5v if the motor RPM is the actual RPM of the car. You can adjust this lower to decrease speed then adjust your PPR to attain the proper contract speed. The drive and the MSU must have the same ME Base speed which is usually the motor nameplate. The PPR adjustments must also be the same in both places.

what was the motor encoder rpm set to under MSU ADJUST. looks like you are only looking at the drive adjustments as john jay says above make sure the MSU adjustment s are correct as well

Well that didn't last very long!

Thanks john jay and Vatorgator I did double check those parameters you suggested. ADC scale is at about 2.57V and I made sure that the RPMs are the same in both MSU and drive.

The car started to run into the overhead! This is only happening on a one floor run from the floor below. If we ran it from multiple floors below the top or bottom to top it would come in fine . It would not run into the pit or thru the bottom landing. It's not overshooting any of the other floors in either direction. Please correct me if I'm wrong but If we have a good floor table the MSU is calculating the slowdown distances at all the landings? with terminal interference from the limits how does the car run into the overhead on a one floor run? Could the top landing mag switch be faulty? I can see that we may or may not get both speed switches on the ETS board on a one floor run, in either direction depending on the floor height but we get both every time on a one floor run into the top landing. It seems like the car is trying to get to full speed on that one floor run. Is there a parameter for an alternate profile for a one floor run? I found ALT PL1 & 2 PROFILE but that looks like it has to do with load weighing. We do not have any load weighing device. Thoughts?

First off, 2.57 is too high. Lower ADC to2.5 volts, then check to make sure the ME Base speed is the same RPM as the Motor Nameplate, in the Drive and MSU. Then raise or lower your speed with the PPR parameters, again in MSU and the Drive. Use the motion averages screen to see when you have attained contract speed.. Also to see when the speed switches are picking. As for the going into the overhead, you may be tripping your ETS switch. Get the speeds correct then see what happens on the one floor run.

Thanks john jay. I will be back there on Tuesday and will go thru those parameters. I will let you know how it turns out.

Good morning all,
john jay you hit the nail on the head! First thing I did was lower ADC Scale to 2.50 and the car immediately responded. I moved the RPM and PPR settings in the drive and MSU to achieve the most stable speeds I could and the car has been running since Tuesday. My natural curious side wants to know what must have changed in the system that necessitated the change in that parameter that was set from the day the car was adjusted 25+ years ago? I am very thankful that the damn thing is running! Thank you all very much for your help with this!

Glad to hear it. It must be those pesky Gremlins again. It would be hard for that unit to run with the ADC at 2.57 unless all the associated parameters, ME Base speed, and the PPR's were jacked also.

Check little yellow relays on board for brake. Usually spares not being used on board.