Yokogawa EJX440A - Manual (Page 44)

<4. Diagnostics>
4-4
IM 01C25T01-01E
4.2.2.1 Blockage Detection
 Limit parameter
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 Limit parameter shown
in below table.
Table 4.2.2 Limit Parameter
# Parameter Threshold value
[1] Lim fDPmax Threshold to detect “A
Blocking” by using Ratio fDP
[2] Lim fDPmin Threshold to detect “B
Blocking” by using Ratio fDP
[3] Lim fSPlmax Threshold to detect “Large
Fluct L” by using Ratio fSPl
[4] Lim fSPlmin Threshold to detect “L Side
Blocking” by using Ratio fSPl
[5] Lim fSPhmax Threshold to detect “Large
Fluct H” by using Ratio fSPh
[6] Lim fSPhmin Threshold to detect “H Side
Blocking” by using Ratio fSPh
[7] Lim BlkFmax Threshold to detect “H Side
Blocking” by using BlkF
[8] Lim BlkFmin Threshold to detect “L Side
Blocking” by using BlkF
[9] Lim DPAvgmax Threshold to detect “ILDB over
range” by using DPAvg and to
detect “Invalid Ref xx” by using
Ref DPAvg
[10] Lim DPAvgmin Threshold to detect “ILDB over
range” by using DPAvg and to
detect “Invalid Ref xx” by using
Ref DPAvg
Table 4.2.3 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 Limit parameters
according to the procedure described in
4.2.2.10.
• Use Device description (DD) file for
parameter setting.
Table 4.2.3 Default Values of Limit Parameter
#
Parameter
Differential pressure
transmitter
Flange
mounted
differential
pressure
transmitter
Diaphragm
sealed differential
pressure/
pressure
transmitter
Absolute
pressure
transmitter
Gauge
pressure
transmitter
Gauge/
Absol ute
pressure
transmitter
EJX110A
EJX115A
EJX130A
EJX120A EJX210A EJX118A
Note 1
EJX438A
EJX310A EJX430A
EJX440A
EJX510A
EJX530A
[1] Lim fDPmax 3 3 10000 10000 10000 10000 10000
[2] Lim fDPmin 0.3 0.3 0.3 0.3 0.3 0.3 0.3
[3] Lim fSPlmax 5 10000 10000 10000 10000 10000 10000
[4] Lim fSPlmin 0.5 0 0 0 0 0 0
[5] Lim fSPhmax 5 10000 10000 10000 10000 10000 10000
[6] Lim fSPhmin 0.5 0 0 0 0 0 0
[7] Lim BlkFmax 0.6 10 10 10 10 10 10
[8] Lim BlkFmin -0.6 -10 -10 -10 -10 -10 -10
[9] Lim DPAvgmax
Note 2
1 1 1 1 1 1 1
[10] Lim DPAvgmin
Note 2
0.05 0.2 -1 -1 0.05 0.05 0.05
Note 1: The default values are set for level measurement. If EJX118A is applied to flow measurement, enter the same value to Limit
parameter [1] to [10] as those of EJX110A.
Note 2: It indicates the threshold value for “ILBD over range” (refer to 4.2.2.5).