Magnetek IMPULSE VG+ Series 3, Инструкция по эксплуатации, Страница: 162 / 183

IMPULSE•VG+ Series 3 Instruction Manual – 07/25/05
6-13
7. If the encoder feedback system checks out and no other mechanical problems can be found, then
something must have changed in the control system.
7.1 Check if the acceleration or deceleration times have been changed (B5-01, B5-02, or C1-02).
7.2 Check if a function that provides an alternate acceleration or deceleration rate has been
enabled or changed. (Quick Stop, Reverse Plug Simulation, Accel/Decel Time 2)
If one of these times are too short, causing torque limited acceleration or deceleration, then the
times should be extended.
8. If none of the above steps has identified a valid problem(s), only then should the speed deviation
detection levels be adjusted.
NOTE: The reaction time necessary to stop a load is limited to the lift of the hoist and the
response time of the hoist brakes. It is desirable to have as fast a fault reaction time as
possible without causing nuisance trips.)
9. Increase Encoder Excessive Speed Deviation Level to no more than 30 (F1-10).
10. After the corrective action has been taken and the fault no longer occurs then the load float time,
C8-10, can be set back to its initial value.
Fault Code: PGO–Pulse Generator Signal Fault
Definition
The pulse generator signal missing fault indicates that the drive has detected a problem with encoder
feedback. This fault will typically occur if the drive doesn’t receive any encoder feedback pulses
while it is commanded to run or encoder wiring has a discontinuity.
Corrective Action
1. Do NOT continue to operate the hoist.
NOTE: Continued attempts to operate the hoist with PGO faults occurring can result in loss
of control of the load under certain circumstances.
2. As a precaution, the load float time, parameter C8-10, should be set to zero until the source of
the PGO Fault has been determined and corrected. Disable PGO hardware detection with F1-20
or F1-21.
3. Check the alignment of the encoder pulse wheel with the sensor head, the encoder shaft coupling
(depending on the type of encoder used), or check for a failed encoder sensor head. If one of
these conditions exist the drive will get erratic pulse signals or no signal at all causing a speed
deviation fault or PGO fault. Repairs to the encoder wheel or shaft coupling should be made
immediately before again attempting to operate the hoist.
4. If the encoder appears to have no mechanical problems, the encoder cable should be checked for
damage and replaced if a problem is found.
4.1 Each of the encoder wires should be check for continuity.
4.2 The wires should be checked for shorts between any two wires.
4.3 The wires should be checked for shorts to the shield or ground.
4.4 Visually inspect the cable for damage that may be causing intermittent problems.
5. If the encoder feedback system checks out, then check for physical obstruction to motor rotation
such as brake failing to open.