User Manual V 1-4.XX User guide

Troubleshooting 12-27
10. Look at the value of Test Data 2. If the value of Test Data 2 is
zero, no problems occurred in this area. If the value of Test
Data 2 is non-zero, there is a problem in the process trim area.
These conditions are generally due to using reference quantities
or gains that are too large to represent in the drive’s number
system. The drive attempts to let the process trim function, but
operation in a limited condition is likely.
To fix a problem in this area, reduce the maximum level of PTrim
Reference (parameter 49) or adjust PTrim Ki (parameter 54) and
PTrim Kp (parameter 55). Adjust PTrim Out Gain
(parameter 60). Refer to the Trim Control Overview section of
Appendix B, Control Block Diagrams, for additional information
about these parameters.
Math Limit Faults — General Comments
The math limit fault is similar to the parameter limit fault. Both faults
indicate that a request was made to do something that the drive cannot
achieve. The 1336 IMPACT drive attempts to honor the request by
using the largest possible data value that is consistent with the
requested data. In many cases, the drive functions under this limited
condition until the data is brought back within a controllable range.
When a math limit fault occurs, evaluate Test Select 2 and Test Data 2
to determine the specific cause. The suggested action depends on the
cause. If drive operation is acceptable as it is, configure the drive to
either indicate a Math Limit warning or to not report the condition.
Math Limit warnings are reported when bit 10 in Fault Select 2
(parameter 22) is clear and bit 10 in Warning Select 2 (parameter 23)
is set. The Math Limit condition is not reported when both bits are
cleared.
Start Up Troubleshooting
Procedures
If you are having problems with the start up procedure, refer to this
table for possible solutions before calling for help.
If Test
Data 2 is:
Then:
Occurred
during:
1 (bit 0) A subtract overflow The process trim error calculation.
2 (bit 1) An overflow
The process trim bumpless calculation
(unable to preset output upon rise of enable
with existing gains).
4 (bit 2) An add overflow The process trim integral calculation.
8 (bit 3) An add overflow The process trim output calculation.
If: Then:
You powered up your drive
and cannot access the
start up routine.
The start up procedure is not supported on a Series A
Human Interface Module (HIM). To verify that you have a
Series A HIM, check the series letter located on the
back side of the HIM or check the HIM version when you
first power up your drive.
You got a Feedback Loss
Fault.
You have specified that an encoder is on the system but
it has been disconnected.