CALIBRATION
AUTOMATIC TUNING (FUNCTION CODE 55)
4 - 2
I-E96-322A
®
•
Calibrate mode enable must be set to disable, <S11> = 0.
•
LVDT status must be good.
To perform the null check:
1. Go to the block address specified in S7. Set the LVDT null
check mode to 1 for the primary LVDT transformer.
2. Go to the block address specified in S11. Set the calibrate
mode enable to 1. This places the IMHSS03 module into cali-
brate mode.
3. Go to the block address specified in S12. Set the GO/HOLD
select to 1 (GO).
4. Wait until the selected LVDT transformer at null point flag
is set in block output N+7, bit 7.
5. Make the necessary adjustments to the servo valve and the
LVDT position to adjust the actuator to its mechanical null
position. For maximum LVDT linearity, the LVDT null point
should occur at the actuator’s midtravel position. When S12 is
in the GO mode, the actuator ramps to and holds at the LVDT
null point (LVDT secondaries have equal voltages). While the
actuator is held at the LVDT null point, the mechanical zero on
the LVDT transformer can be adjusted until the actuator is at
its midpoint position.
6. If there are redundant LVDT transformers, go to the block
address specified in S7. Set the LVDT null check mode to 2 for
the backup LVDT transformer.
8. When the adjustments are complete, set GO/HOLD select
to a 0 (HOLD), set calibrate mode enable to a 0 (DISABLE) and
set null check to 0 (DISABLE).
AUTOMATIC TUNING (FUNCTION CODE 55)
To start automatic tuning, the MFP module must be communi-
cating with the IMHSS03 module and the following conditions
must be met:
•
The turbine is off-line.
•
The servo valve or I/H converter (for turbine hydraulic sys-
tem) must be in the controlling position and functioning
properly.
•
The multi-function processor module has function code 55
in its configuration.