DRIVE FAULTS
95
ERROR/FAULT CODE PROBABLE CAUSE/ — CORRECTIVE ACTION
so than a DCU or PCU software problem. A likely cause is severe
electrical interference. Check for:
Faulty EPROM’s or socket connections at U13, U14, U39 or U40.
Ensure that all panel relays have working R/C coil suppression.
Include relays that may be operating door opener equipment.
Look for relays where the +24V and 115VAC signals are being
switched in the same relay. There must be arc barriers between
contact poles to avoid “spark splash” from 115 VAC circuits into 24
VDC logic.
Check for intermittent grounds in the power circuit and in 24Vdc signal
wiring.
Noise generated over the encoder feedback, power supply, or Drive
Control PCB can cause this fault. Verify all connections and verify that
the Drive Control PCB is properly grounded.
This fault is usually caused by electrical noise causing the DSD 412
microprocessor to malfunction. If this occurs when the car is
stationary, the car controller can quickly reset it. An elevator
passenger doesn’t see any effect.
Prot CORRUPTED NVRAM DATA – The NVRAM has lost parameter set
up data.
This fault will occur if the battery within NVRAM chip U56 is
weak. The drive display will show ‘
Prot” if a loss of data is detected
when power has been re-applied, and the processor attempts to load
in default values while the NV-Protect switch is in the ‘safe’ ON
position. replace U56 every 8 years.
" P.L. " POWER LOSS - Loss of 115 VAC control power. — Check cable
connection at TB3 of Power Supply Assembly A4. Ensure that control
power is always above 92 VAC.
" – – – " BLOWN FUSES or loss of 3 phase input power. – Check for blown line
fuses. If fuses are not blown, verify that AC input voltage to drive is
present. Verify that power supply voltages are valid at TP1, 2, 3, & 4
on the main PCB. Check connections to the Armature Interface PCB
and ribbon cable at J4.
F929 Motor field current does not reduce to near zero within 6 seconds.
Verify motor field current with an independent clamp-on DC
ammeter.
Probable causes:
Incorrect phasing of Vac supply to field control module. Provide
correct single phase supply wiring per connections shown in Figs. 2.1
of this manual:
Faulty SCR/Rectifier power module for motor field. Replace.
*may occur during Self-Tune (Fctn #997) or Self-Diagnostic (Fctn
#998).
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