<7. HART Communication>
7-41
IM 01C25W05-01EN
■ Alarm LCD display
If ILBD detects an error, the detection result
information is indicated in alarm number AL.88 or
AL.89 and on the LCD.
AL.88 indicates a condition in which errors cannot
be detected, and AL.89 indicates that an error has
been detected.
F0720.ai
Figure 7.3.7 Display example of Pres 1 Side
Blocking
For the advanced diagnostic alarm display
information shown on the LCD, see Table 8.3.
CAUTION
“Invalid Ref xx” and “ILBD over Range” alarms
are not reflected in analog alerts.
7.3.2.2.6 Condition Confirmation
After the transmitter is installed, confirm that the DP
value is normal and stable and that the pressure
fluctuation is sufficient for blockage detection.
■ Stable pressure value
Under normal operating conditions, monitor the DP
value fluctuation for 10 minutes, and confirm that
the variation is less than 10%.
• Recalling the DP parameter
Recall
parameters
[Root menu] → Process variables
→View device vars → DP
If the DP variation is 10% or higher, blockage
detection will not be possible because errors will
appear in the statistically processed pressure
fluctuation values. Review the process conditions.
■ Pressure fluctuation value
CAUTION
• If the liquid’s pressure fluctuation is small,
blockage detection does not work properly.
• The pressure fluctuation may be small in
the case of level measurement or pressure
measurement of tanks or when gases are
measured.
Check that the fDP, fP2, fP1, and BlkF values meet
the conditions shown in the following table.
• Recalling the pressure fluctuation parameters
(fDP, fP1, fP2)
Recall
parameters
[Root menu] → Diag/Service → Diag
Parameters → ILBD parameters →
Status → Fluct Variables → fDP/fP2/
fP1
• Recalling the blockage level parameter (BlkF)
Recall
parameters
[Root menu] → Diag/Service → Diag
Parameters → ILBD parameters →
Status → Diag Variables → BlkF
Table 7.3.3 Pressure fluctuation parameter values
required for blockage detection
Parameter
Condition
fDP
7×10
-10
or higher
fP2
1×10
-10
or higher
fP1
1×10
-10
or higher
BlkF
–0.5 to 0.5
● fDP is insufficient.
If fDP does not meet the condition, none of the
blockage detection algorithms will be executed.
● Only fDP meets the condition.
If fP2 and fP1 do not meet their conditions, only
“A Blocking” and “B Blocking” can be detected.
● fDP and fP1 meet the conditions.
If fP1 does not meet the condition, “Pres 1 Side
Blocking” and “Large Fluct Pres 1” cannot be
detected.
● fDP and fP2 meet the conditions.
If fP2 does not meet the condition, “Pres 2 Side
Blocking” and “Large Fluct Pres 2” cannot be
detected.
● fDP, fP2, and fP1 meet the conditions.
All ILBD results can be detected even when
BlkF does not meet the condition.
