<7. HART Communication>
7-35
IM 01C25W05-01EN
CAUTION
• Ref fDP must be a value larger than the
level specified in Table 7.3.2 of subsection
7.2.2.6. If sufficiently large Ref fDP cannot
be obtained, blockage detection will not be
possible.
• The blockage detection function must be
verified through blockage simulation test. A
blockage simulation test is performed using
a valve (see subsection 7.3.2.2.8).
[Differential pressure measurement]
Reference
fluctuation
Parameter result
Simulation test
Blockage detection that can be used
Ref fDP: OK
Ref fP2: OK
Ref fP1: OK
Ref BlkF: OK
→
• Low pressure side
blockage simulation test
• High pressure side
blockage simulation test
• Both side blockage
simulation test
• A/B Blocking (detection based on fDP and Ref fDP)
• Pres 2 Side Blocking (detection based on fP2 and Ref
fP2 )
• Pres 1 Side Blocking (detection based on fP1 and Ref
fP1)
• Pres 1/Pres 2 Side Blocking (detection based on BlkF)
Ref fDP: OK
Ref fP2: OK
Ref fP1: OK
Ref BlkF: NG
→
• Low pressure side
blockage simulation test
• High pressure side
blockage simulation test
• Both side blockage
simulation test
• A/B Blocking (detection based on fDP and Ref fDP)
• Pres 2 Side Blocking (detection based on fP2 and Ref
fP2 )
• Pres 1 Side Blocking (detection based on fP1 and Ref
fP1)
Ref fDP: OK
Ref fP2: NG
Ref fP1: OK
Ref BlkF: NG
→
• High pressure side
blockage simulation test
• A Blocking (detection based on fDP and Ref fDP)
• Pres 1 Side Blocking (detection based on fP1 and Ref
fP1)
Ref fDP: OK
Ref fP2: NG
Ref fP1: NG
Ref BlkF: NG
→
• Both side blockage
simulation test
• B Blocking (detection based on fDP and Ref fDP)
[liquid level measurements]
Reference
fluctuation
Parameter result
Simulation test
Blockage detection that can be used
Ref fDP: OK
→
• Blockage simulation test
• B Blocking (detection based on fDP and Ref fDP)
