Construction Mode
2-42 Manual # 42-02-7223 C1
Speed Loop Gains (System 12 SCR Drive)
If there is oscillation while running:
1. On the Configuration > Drive > Control tab, slowly decrease PID-Standard Proportional
error and Integral error until oscillation stops. Verify the Option-Start gain (normal) is
not checked.
In the following steps, adjust the response of the car to reduce empty car rollback while avoid-
ing the oscillations that can occur if too much feedback is adjusted into the system. For these
adjustments, monitor Tachometer and Raw Pattern on the iView Virtual Oscilloscope.
1. The empty car may drift up due to counterweighting even when an attempt is made to
move it down. Increase PID-Standard Proportional error on the Configuration > Drive >
Control tab slowly while watching for severe overshoot or oscillations, such as rapid jig-
gling or slow bobbing. If jiggling begins, decrease PID-Standard Proportional error.
While decreasing it, note a narrowing of the difference between pattern and tach signals.
2. Next, increase PID-Standard Integral error slowly. Now there will be less rollback at
takeoff and the car will reach the desired speed faster. Too much Integral gain will cause
a speed overshoot or a slower bobbing oscillation.
3. If the car snaps away from the floor, increase Speed pick delay 1 on the Brake > Timers
tab. At this point, a little rollback is not critical as later adjustments will compensate for
it.
4. Monitor the actual car motion by viewing Raw Pattern on the Virtual Oscilloscope. Posi-
tive voltage should indicate the up direction and negative voltage the down direction.
While monitoring, adjust the values of PID-Standard Proportional and Integral gains to
achieve best response. For now, leave PID-Standard Differential Error = 0.00.
Error Compensation If oscillation or rollback is still excessive, try adjusting Error
compensation on the Configuration > Drive > Control tab. The default setting for this parame-
ter is 0.250.
1. Adjust Error compensation upward in 0.250 increments, sending the new value to the
controller and running the car each time to see the effect on oscillation or rollback.
The final Error compensation setting should be below 9.0. The goal here is to obtain acceptable
response during Inspection operation of the elevator. Fine tuning for turnover to normal opera-
tion is accomplished in Section 4 of this guide.
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