Yokogawa EJX440A - Manual (Page 52)

<4. Diagnostics>
4-12
IM 01C25T01-01E
 Start of Sampling
The sampling of reference value is carried out for
180 sec, which is the default value set to Diag
Period.
1) Confirm that the sampling period (
Diag Period)
is set to 180 sec.
2) Set “Reference” to Diag Mode.
The sampling starts soon after the setting.
IMPORTANT
• For the each parameter, the one value is
given. If Reference is set to Diag Mode
again, the value is updated and overwritten.
• If the power supply is shut down during the
sampling, Diag Mode becomes “Stop”. Set
“Reference” to Diag Mode in order to carry
out the sampling again.
 End of Sampling
After about 180 sec, the sampling automatically
finishes. The “Reference” setting of Diag Mode
moves automatically to “Calculation”.
Confirm that the setting of
Diag Mode moves to
“Calculation”.
 Reference Values
Confirm the latest values are obtained into the
following parameters.
• Ref fDP
• Ref fSPl
• Ref fSPh
• Ref BlkF
• Ref DPAvg
 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.
• Use Device description (DD) file for
parameter setting.
 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.