CALIBRATION
AUTOMATIC TUNING (FUNCTION CODE 55)
4 - 4
I-E96-322A
®
Initial Calibration (Function Code 55)
To calibrate the LVDT transformer and actuator with the HSS
module, the MFP module must be communicating with the
HSS module and the following conditions must be met:
•
Demodulator gain tuning must be complete.
•
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.
•
The calibrate mode enable must be set to disable,
<S11> = 0.
To calibrate the HSS module:
1. Verify that the block address specified in S9 contains the
proper number of calibration cycles (from 1 to 8).
2. Verify that the block address specified in S8 contains the
proper calibration stroke time. Values are selected in seconds.
Calibration stroke times under 30 seconds are not recom-
mended for on-line tuning.
3. Go to the block address specified in S11. Set the calibrate
mode enable to 1, <S11> = 1. This places the HSS module into
calibrate mode.
4. Go to the block address specified in S12. Set the GO/HOLD
select to 1 (GO).
5. The HSS module drives the actuator to the 100% position
at the selected stroke time specified in <S8>. While the actua-
tor is held against the 100% end of travel, the LVDT differential
voltage at 100% is recorded. If redundant LVDT transformers
are configured, then the voltage at 100% will be recorded for
both LVDT transformers.
After recording the 100% reading, the HSS module drives the
actuator to the 0% position at the selected stroke time. While
the actuator is held against the 0% end of travel stop, the LVDT
differential voltage at 0% is recorded. If redundant LVDT trans-
formers are configured, then the voltage at 0% will be recorded
for both LVDT transformers.
NOTE: The position feedback output block N will display the current
valve position read by the primary LVDT transformer.