Auto Tuning Malfunctions (Series A & B) - Allen-Bradley 1395 Troubleshooting Manual

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3-34 Malfunctions Not Indicated by a Fault
Auto Tuning Malfunctions
(Series A & B)
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24V Unregulated Supply
The 24V unregulated power supply is used to supply power for SCR gate
firing signals, the 24V ECOAST string, the pre–pilot relay, and the
"faulted" relay. The components include a step–down transformer, rectifiers
and filter capacitors located on the upper left side of the PSI/Switcher
board. A failure will exhibit a drive fault CP–15 "24V Power Supply Loss".
Follow the procedure below if a 24V power supply malfunction is
suspected.
1. Measure the +24V supply level on the PSI/Switcher Board. With a
DMM on the 200 VDC range, measure the potential from TP25 to TP6.
The voltage should be 24V DC 6.0V .
2. Measure the 20 VAC source for the 24V supply. With a DMM on the 200
VAC range, measure from cathode of D12 to the cathode of D13. The
measured potential should be 20 VAC 6VAC. If no potential is measured
check fuse F2 on the PSI/Switcher board. If the AC potential is correct
and there was no voltage measured in step 1, replace the PSI/Switcher
board.
3. If after replacing F2, the fuse opens again, board replacement may be
necessary.
The Autotune function of the 1395 allows the user to tune the current and
velocity loops in a minimum amount of time and effort. The Autotune
function is executed using the Bulletin 1300 Programming Terminal and the
standard logic control, dictated by the application. Most malfunctions that
occur are indicated with a fault response from the 1395. The fault messages
that are associated with Autotuning are VP–40 through VP–49 and CP–16,
CP–18, CP–90 through CP–121. These fault messages are fully explained
in Velocity Processor and Current Processor fault description sections.
Autotune measurement tests require the same considerations that normal
operation does. Control of the drive ultimately is executed from the selected
Logic Command. The parameters associated with Autotune must be
properly programmed. The drive set–up parameters must be accurately
programmed (i.e. Base Speed, Rated Armature Current Levels, Rated Field
Current Levels, etc.) to allow for controlled and safe operation. All
ECOAST and other related protective type circuits must be fully operational
before attempting to use Autotune.
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