Yokogawa EJA440E - Manual (Page 62)

<4. Diagnostics>
4-15
IM 01C25T01-06EN
Table 4.4 Requirements to apply ILBD
Condition
fDP 7×10 -10 or more
fSPI 1×10 -10 or more
fSPh 1×10 -10 or more
BlkF -0.5 to 0.5
 fDP is not enough.
No blockage can be detected if fDP is not larger
than the specified value.
 Only fDP is enough.
“A Blocking” or “B Blocking” can be detected
if fSPl and fSPh are not larger than specified
values.
 fDP and fSPl are enough.
“H Side Blocking” and “Large Fluct H” can not
be detected if fSPh is not larger than specified
value.
 fDP and fSPh are enough.
“L Side Blocking” and “Large Fluct L” can not
be detected if fSPl is not larger than specified
value.
 fDP, fSPl and fSPh are enough.
All alarm modes can be detected even if BlkF is
not within the specified values.
4.2.2.7 Obtain Reference Values
The pressure fluctuation values are reduced
when the impulse line is plugged. Therefore, the
reference value is required to determine the degree
of reduction.
IMPORTANT
• If the impulse line is about to be plugged at
the time when a reference value is obtained,
blockages cannot be detected accurately.
The impulse lines on both the high-pressure
and low-pressure sides need to be cleaned
before a reference value is obtained.
• All air bubbles need to be adequately purged
before a reference value is obtained.
• Reference values must be obtained under
operating condition.
 Start of Sampling
The sampling of reference value is carried out for
180 seconds, which is the default value set to Diag
Period.
1) Confirm that the sampling period (
Diag Period)
is set to 180 seconds.
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 seconds, 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
• Procedure to call up the display
DD and DTM
(excluding EJX_
HART 5[1.2])
[Root Menu] → Diag/Service
→ Diag Parameters → ILBD
parameters → Status → Diag
Reference → Ref fDP/Ref fSPl/Ref
fSPh/Ref BlkF/Ref DPAvg
EJX_HART 5[1.2]
DTM
Diag and Service → Advanced
Diag Configuration → Impulse Line
Blockage Detection → Ref fDP/Ref
fSPl/Ref fSPh/Ref BlkF/Ref DPAvg