The feedback from the M, B1 or B2 contactors shows a contactor in the open position when it
should be closed. Use Extra Byte 1, 2 or 3 to determine the reason for the fault and how to
correct it.
Extra Bytes 1-0: Both SF1 and SF2 are energized but the M contactor feedback shows it open
(de-energized). The M contactor should close (energize) whenever the safety string is made
and the SAF relays are both energized.
The machine room board monitors the normally closed auxiliary contact of the M contactor.
This contact is normally wired to an input on the Machine Room SRU board but can be moved
to another input. The input should be powered when the contactor is open and unpowered
when the contactor is closed.
Extra Bytes 2-0: The controller has been asserting a pick or hold command to the brake for at
least one second but one or more of the B1 contactors feedback show they are not energized.
Extra Bytes 3-0: The controller has been asserting a pick or hold command to the brake for at
least one second but one or more of the B2 contactors feedback show they are not energized.
Extra Bytes 1-0: If the M contactor does not energize at all, check the safety circuit for an open
switch. The coil of the M contactor gets its power from the safety circuit.
Also check the SF1 and SF2 relays. Verify the relays are properly seated in the sockets and do
not have any bent pins.
If the M contactor does energize, verify the normally closed feedback input on the Machine
Room SRU board is powered when contactor is de-energized, and not powered when
contactor is energized.
Verify the auxiliary contactor is securely attached to the M contactor. If the connection is
loose, try to snap it back on more snugly.
Extra Bytes 2-0: If the B1 contactor does energize, verify that the normally open feedback inputs
on the Machine Room SRU board are powered when contactor is de-energized and not powered
when contactor is energized.
Verify the auxiliary contactor is securely attached to the B1 contactors. If a connection is loose,
try to snap it back on more snugly.
Extra Bytes 3-0: If the B2 contactor does energize, verify that the normally open feedback
inputs on the Machine Room SRU board are powered when contactor is de-energized and not
powered when contactor is energized.
Verify the auxiliary contacts are securely attached to the B2 contactors. If a connection is
loose, try to snap it back on more snugly.
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