National Instruments FP-3000 User Manual
Page 124
Appendix F
Troubleshooting
FieldPoint FP-3000 User Manual
F-6
www.ni.com
The actual mode of a block
switches values.
A block, such as a PID, may switch modes between
Iman
and
Auto
. This means that there is a communications problem
between the PID and the downstream AO block.
•
Check the schedule. The execution of the PID, AO, and the
communication between them might be scheduled too
close to each other. Space these events further apart and
re-download the configuration.
•
Check if the stale limit is set correctly for the loop. The
stale limit defines how many old values to accept before
changing
Status
to
Bad
. If the block that is subscribing
the data is executing at twice the rate of a block that is
publishing data, the stale limit must at least be set to 2.
PID block output seems
incorrect.
Make sure that you have set the value of the tuning parameters
like
RATE
,
GAIN
and
RESET
correctly.
Typical values for
GAIN
,
RESET
, and
RATE
are:
GAIN
RESET
RATE
Pressure control
1.2
3.33
0.8
Temperature control
3.0
25.0
10.0
Flow control
0.33
1.11
0.0
Level control
1.9
16.67
2.7
Cannot access or view the
parameters added by National
Instruments.
Make sure that the Device Descriptions are installed in the
correct location. Refer to the section
in Chapter 2,
Installation and Configuration
Cannot change the values of
certain parameters.
Many configuration parameters of function blocks can be
changed only when the block is in
OOS
mode. Set the mode to
OOS
and then change the configuration parameters.
Table F-3. Generic Software Configuration Problems (Continued)
Problem
Solutions