Yokogawa EJX930A - Manual (Page 147)

<Appendix 8. Advanced Diagnostics>
A8-3
IM 01C25T02-01E
A8.2.1 Blockage Detection
 DIAG_LIM
When the parameter based on pressure fluctuation
exceeds the preset value, EJX diagnoses an
impulse line as blockage and gives an alarm. The
threshold values are set to DIAG_LIM [1] to [8] in
the SENSOR Transducer block.
TableA8.2 shows the default values at the factory
setting, which are different according to the model.
NOTE
• When ILBD is performed for the first time,
use the default value. If the pressure
fluctuation amplitude is low or a false alarm
is often generated after ILBD is performed,
change the values of DIAG_LIM according to
the procedure described in A8.2.10.
• Use Device description (DD) file for
parameter setting.
DIAG_LIM
# Parameter Threshold value
[1] fdpmax Threshold to detect “A Blocking” by
using RATIO_FDP
[2] fdpmin Threshold to detect “B Blocking” by
using RATIO_FDP
[3] fsplmax Threshold to detect “Large
Fluctuation of Low Side” by using
RATIO_FSPL
[4] fsplmin Threshold to detect “Low Side
Blocking” by using RATIO_FSPL
[5] fsphmax Threshold to detect “Large
Fluctuation of High Side” by using
RATIO_FSPH
[6] fsphmin Threshold to detect “High Side
Blocking” by using RATIO_FSPH
[7] blkfmax Threshold to detect “High Side
Blocking” by using VALUE_BLKF
[8] blkfmin Threshold to detect “Low Side
Blocking” by using VALUE_BLKF
[9] dpavgmax Threshold to detect “Outside
Diagosis Range” by using VALUE_
DPAVG and to detect “Invalid
Ref xx” by using REFERENCE_
DPAVG.
[10] dpavgmin Threshold to detect “Outside
Diagosis Range” by using VALUE_
DPAVG and to detect “Invalid
Ref xx” by using REFERENCE_
DPAVG.
Table A8.2 Default Values of DIAG_LIM
INDEX Parameter
Differential pressure
transmitter
Flange
mounted
differential
pressure
transmitter
Diaphragm
sealed
differential
pressure/
pressure
transmitter
Absolute
pressure
transmitter
Gauge
pressure
transmitter
Gauge/
Absolute
pressure
transmitter
EJX110A
EJX115A
EJX120A EJX130A
EJX135A
EJX210A EJX118A Note 1
EJX438A
EJX310A EJX430A
EJX440A EJX510A
EJX530A
[1] fDPmax 3 3 3 10000 10000 10000 10000 10000
[2] fDPmin 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3
[3] fSPlmax 5 10000 5 10000 10000 10000 10000 10000
[4] fSPlmin 0.5 0 0.5 0 0 0 0 0
[5] fSPhmax 5 10000 5 10000 10000 10000 10000 10000
[6] fSPhmin 0.5 0 0.5 0 0 0 0 0
[7] blkfmax 0.6 10 0.6 10 10 10 10 10
[8] blkfmin -0.6 -10 -0.6 -10 -10 -10 -10 -10
[9] dpavgmax
Note2
1 1 1 1 1 1 1 1
[10] dpavgmin
Note2
0.05 0.2 0.05 -1 -1 0.05 0.05 0.05
Note 1: The default values are set for level measurement. If EJX118A is applied to the flow measurement, set the same value to
DIAG_LIM [1] to [10] as those of EJX110A.
Note 2: It indicates the threshold value for ILBD over range (refer to A8.2.5.3).