A-10
Appendix A Maintenance and Troubleshooting of this Device
(B) The variation of the index when there is a clog is small.
In this case, although variation in the index is relatively small under normal operating conditions,
the value of the index is almost the same as with simulated clogging, as shown in the figure below.
In this case, the index value under normal operating conditions is similar to that with clogging,
or the index value is almost the same even when clogging occurs. In either case, it is necessary to
examine the cause and to minimize this effect. Use the following guidelines for adjustment.
Index value Index value
Maximum value under normal
operating conditions
Minimum value under normal
operating conditions
Maximum value under simulated
clogging
Minimum value under simulated
clogging
The dierence with that of
the clog simulated condition is small
Cannot make a distinction
as values are overlapped
Normal condition Simulated clogging
Maximum value under normal
operating conditions
Minimum value under normal
operating conditions
Maximum value under simulated
clogging
Minimum value under simulated
clogging
Normal condition Simulated clogging
Guidelines for parameter adjustment
Phenomenon Adjustment
Since the process variable fluctuates and there is
always low-frequency pressure fluctuation, the
value of the index is small even under normal
operating conditions. The standard deviation is
relatively large.
Increase the Press Freq Filter Constant in steps
of 0.02–0.05.
The PV does not change and the standard
deviation is also small. The frequency of the
original pressure fluctuation is low and the index
value is small. (The reference index value is 0.1
or less under normal operating conditions.) Fluid
viscosity is high.
Change the Press Freq Index Sensor Selection.
If the present value is “DP, 120 ms”, set it to
“DP, 240 ms,” and if the present value is “DP,
240 ms,” set it to “DP, 360 ms.”
The magnitude and frequency of the original
pressure fluctuation are acceptable. (The
reference index value is 0.2 or more under
normal operating conditions.) However, the
value is almost the same when there is clogging.
Decrease the Press Freq Filter Constant in
steps of 0.02–0.05.
To Next Page
Loading...