Tac 50-04 681 fault

Has anyone ever had a 681 fault on a Tac50-04 MRL? Problem is intermittent and all signs point to the absolute encoder.

Whats the fault description? It's been a while but I have adjusted several 50-04's when I used to work at TKE.

Encoder response failure. Encoder failed to return a position reading upon request.

Encoder response failure. Encoder failed to return a position reading upon request. Elevator runs fine for a couple of days then shuts down at the initial start of a run, never in flight. Checked encoder power supply, changed out encoder interface card, also checked MC1 & BRK1 contactors still no luck.

How's your levelling accuracy, or more importantly repeatability? Double check how close the counts are.

Likely swapping the encoder will resolve the issue, but you might want to check for buildup on the gov and idler sheaves, and make sure the encoder is properly secured.

Which MRL machine? German or Torin? absolue encode is on the machime change it perform a ecnoder calibration boom goes the dynomite

Leveling is usually pretty accurate & counts are close. Encoder seems secure but I'll check the governor for any build up. Thanks

It's a German machine. Seems that to perform an encoder alignment the ropes need to be clear of the sheave. Smh...

Negative I dont remember the command but you dont hsve too. That encoder has goofy way it connecte to the shaft pay close attention when you change it.

Thanks. Will do, glad there's no need to remove ropes from sheave.

I've changed two of these before without pulling the ropes. On a car today at another job no luck kept getting encoder faults had to remove rope and run thru the set up like done from new contstruction. So now I'm not so sure sorry.

Doing this encoder alignment process now. Replaced encoder for 690 fault. Did not resolve issue. Swapped all boards. Brakes are picking. Frustrated.

On my t4's when I got those encoder response failures its nothing to do with the encoder at all. The car was unable to make run due to something in the logic so the encoder timed out due to no movement. I've had aux contacts cause it, I cant remember the name of the relay but one of the contacts is after saf3 and between the S coil has caused it. this is on a t4/tac50 so it does not apply to the 04's but the point I'm making look in other places then the encoder for reasons why the car did attempt to move but the logic was not correct to allow a run.

Also check the Power Supply to the Encoder for "ripple". Grounding and shielding could also cause those problems.

tac 50-04 very affected by noise make sure grounding is perfect only on one end

Is your low voltage wiring completely separate from high? I have a similar problem from noise because my LV is wire tied to my HV. I am getting 10VAC on my BSLM which is causing interference on my BKE BKD I/O. Do you have logfiles setup?

I just received a notice to remove the 1/4 " bolts from the MC1 relay isolation. Thanks for the heads up. ?? Anyone know about this?

im a bit late but I agree with sbrmilitia. ive had aux contacts that were bad that have thrown me for days of troubleshooting.