CALIBRATION
AUTOMATIC TUNING (FUNCTION CODE 55)
I-E96-322A
4 - 3
Demodulator Gain
The HSS module automatically tunes the demodulator gain
using the same techniques a technician would use to manually
tune the gain. The auto tuning function selects the lowest gain.
The actuator moves to the 100 percent and zero percent posi-
tions. At each position the LVDT secondary voltage is read. If
the 100 percent position secondary voltage is less than 8.5
volts or the zero percent LVDT secondary voltage is greater
than -8.5 volts, the demodulator gain is increased. This proce-
dure repeats until the 100 percent position LVDT secondary
voltage is greater than 8.5 volts or the zero percent position
LVDT secondary voltage is less than -8.5 volts. Then the
demodulator gain is set to the next lower value.
The automatic tuning error bit is set if the lowest demodulator
gain causes the LVDT secondary voltages to go out of range or
the highest demodulator gain causes the LVDT secondary volt-
ages to remain below range (±5 VDC). This error bit indicates
that the automatic tuning procedure was unable to provide an
optimum gain value. A less than optimum gain value produces
inaccurate position feedback information from the LVDT trans-
former, so corrective action is required.
To automatically tune the demodulator gain:
1. Set the demodulator gain constant to 0, <S16> = 0. This
initiates the tuning procedure.
2. Observe the module status on the output block N+6, bits 0
and 1. If these bits have a binary value of 0, tuning is in
progress. When tuning is complete, the binary value of these
bits is 1.
3. If these bits have a binary value of 3, then an error has
occurred during the automatic tuning procedure. All block out-
puts will show bad quality. The other error bits in the module
status output block N+6 and the LVDT status output block
N+7 will indicate the error. Refer to
for corrective
action. After correcting the error, repeat the demodulator gain
tuning procedure.
NOTE: To clear the automatic tuning of parameters (ATOP) error
status and bad output qualities without performing another auto-
matic tuning of parameters, send any new demodulator gain value
to the IMHSS03 module.
If an error occurs during tuning, the previous value (before the
ATOP procedure was initiated) is displayed as the gain value. If
the error occurs while the gain is at the highest or the lowest
value, the error is probably an out of range condition. If this
happens, the controller gain remains at the out of range value
to indicate that the error occurred because of an out of range
condition.
