Yokogawa EJA440E - Manual (Page 63)

<4. Diagnostics>
4-16
IM 01C25T01-06EN
 Invalid Ref F, SPH, SPL, or DP
When the enough reference fluctuation value is
not obtained, an alarm of invalid reference value
for each parameter is generated and also the ILBD
operation is not carried out.
Confirm the alarm of
Invalid Ref F, SPH, SPL, or
DP is not displayed in Diag Error.
If an alarm of
Invalid Ref F, SPH, SPL, or DP is
generated, consider the process condition or obtain
the reference fluctuation values again.
NOTE
Even if an alarm of Invalid Ref F, SPH, SPL, or
DP is generated, “Calculation” in Diag Mode is
kept.
4.2.2.8 Capability Test of Blockage
Detection Operation
Before performing the ILBD operation, check the
capability of the blockage detection operation.
The simulation test is performed by closing motion
of a three-valve manifold or stop valve. When
simulated blockage occurs, confirm that an alarm is
generated.
NOTE
The fluctuation amplitude of atmospheric
pressure is nearly zero with pressure or level
measurement. In such case, simulate the
blockage detection by closing the valve where
the fluctuation existed.
 Simulation of High-pressure Side
Blockage
1) Close the high-pressure-side valve.
2) Confirm the value of Pres is stable. If not,
open the valve a little.
3) Set “Calculation” to Diag Mode so as to start
blockage detection operation.
4) Check that an alarm of “H Side Blocking” is
generated after the time that consists of Diag
Period and Diag Supp Count passed.
5) Check also the operation of the analog alert if
an analog alert is set.
6) Open the valve completely and check that
there are no alarms.
 Simulation of Low-pressure Side
Blockage
1) Close the low-pressure-side valve.
2) Confirm the value of Pres is stable. If not,
open the valve a little.
3) Set “Calculation” to Diag Mode so as to start
blockage detection operation.
4) Check that an alarm of “L Side Blocking” is
generated after the time that consists of Diag
Period and Diag Supp Count passed.
5) Check also the operation of the analog alert if
an analog alert is set.
6) Open the valve completely and check that
there are no alarms.
 Simulation of Both-pressure Side
Blockage
1) Close the both-pressure-side valves.
2) Confirm the value of Pres is stable. If not,
open the valve a little.
3) Set “Calculation” to Diag Mode so as to start
blockage detection operation.
4) Check that an alarm of “B Blocking” is
generated in the Diag Error after the time
that consists of Diag Period and Diag Supp
Count passed.
5) Check also the operation of the analog alert if
an analog alert is set.
6) Open the valve completely and check that
there are no alarms.
4.2.2.9 Start ILBD Operation
If process condition and capability to detect a
blockage are confirmed, you can start the ILBD
operation according to the following procedure.
1) Check the value of sampling period ( Diag
Period).
2) Check the number of times that detect the
blockage consecutively in order to give an
alarm ( Diag Supp Count). The default value
at the shipment is set to 3 times.
3) Set “Calculation” to Diag Mode.
If the reference value has not yet been
obtained, set “Reference” to Diag Mode.
After obtained the reference values, the
ILBD starts automatically. At the same time,
Diag Mode changes automatically from
“Reference” to “Calculation”.