I have an Otis 411 with a Magnetek DSD 412 drive. when the elevator begins to run. M and ME pick but BP doesn't pick to make the brake coil circuit. Drive sends voltage to the armature but the brake doesn't pick. It appears that the BP-OUT gate on the drive terminal is not closing the circuit to pick BP coil. I believe that the mother board sends a serial link communication to the drive to make the circuit. all safety and door locks circuits are made. drive runs for about 5 seconds and then gives up. Has anybody ever had this problem.

page 99 of 412 manual function number 981 this is the input output verification for troubleshooting. look for the led segment that corresponds to tb1-83 which is the output transistor for the BP circuit. if the car attempts to run, and the corresponding led for tb1-83 lights up, then the dsd412 is initiating the output, this way you can tell if the output should be coming on, if led is lit, and output not on, then bad transistor output,

that is very interesting. I found the page you are talking about and will return to the site Monday. now if the led is not lit when trying to run, can assume its a problem of the controller not telling the drive to pick the brake? thanks

another interesting thing about this controller is that when I put it on controller inspection I get a 2812 fault ( door closed, door close limit input conflict) but my door limits are correct, and then it opens the safety string and placed the drive on estop.

Do you have the service tool?
Go to M-2-1-1 this should show the doors closed
With the doors closed,
Are your MLB lll LEDs on for BDS FDS FGS RDS RGS TDS ?
Is your door limit open?
Do you have 0vdc at JF4-3?
Is DCL in M-3-1 active?

I have a tool on the way, should be here Tuesday or Wednesday. Ill let you know what I find. thanks for all the help

I suspect that when your car is placed on inspection, you are losing door power. There is a parameter that allows you to either energize or de-energize your doors during inspection operation. I would see if your doors are dead when on TOCI.

What kind of drive faults do you pick up? I would clear the drive fault log, try to run and then check the log. Have you checked the NO aux contacts of ME?

I'm pretty sure doors are powered up. they close when placing the car on inspection. I will double check

I seem to be having an intermittent problem with the GS_P input. is it tied to the DCL, gate lock and Hatch locks?

xxx_P are redundant inputs to the Safety Pal circuitry. example FGS is input to front gateswitch and the same input labeled FGS_P is input for the redundant safety pal circuit. both inputs are together, and are fed from the front gate switch, basically one input going to 2 different parts of the circuit board, and they must agree. how do you know you are having an intermittent GS_P input? i believe you can look at the MLB input for FGS, and also look at the PAL Safety input, for FGS_P they should both be Hi when the doors are closed. my print shows RGS and FGS for front and rear gate switches. can't find a GS_P input

I believe the PAL INPUTS toggle before each run when the controller does the input/output check.

good to know magic thanks

I believe the problem was a stretched GAL limit switch chain that was not opening the DCL contacts. once we repaired that problem the elevator has been running.

the GS_P led is below NOR led and above NTB led . I can not find in prints either. I believe it is an internal check.