<7. HART Communication>
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IM 01C25W05-01EN
7.3.2.2.3 Operation Parameters
■ Diag Mode
The impulse line blockage detection function
is performed by specifying three modes (Stop,
Calculation, Reference) using the Diag Mode
parameter.
• Recalling the operation parameter (Diag Mode)
Recall
parameters
[Root menu] → Diag/Service
→ Diag Parameters → ILBD
Parameters → Configuration → Set
Diag Mode (method)
Diag Mode
Mode
Description
Stop
Stops blockage detection operation.
Calculation
Executes blockage detection operation.
Alarms are generated on the basis of
blockage detection results.
Reference
Acquires pressure fluctuation reference
data needed for blockage detection
and updates the reference data. After
reference data is acquired, the mode
automatically switches to Calculation.
To start blockage detection, select Calculation.
To change the alarm or threshold settings, select
Stop as you need to stop the diagnostics.
To acquire or reacquire the pressure fluctuation
reference value, select Reference.
NOTE
If the impulse line blockage detection (ILBD)
parameter is set using the online parameter
Hotkey’s ILBD of the DTM Diag Mode is
automatically set to Stop. When parameter
setting is complete, Diag Mode returns to the
original mode.
NOTE
If the impulse line blockage detection (ILBD)
parameter is set using the “Download to device”
of the DTM, Diag Mode is automatically set to
Stop.
■ Diag Period
Values such as fDP and BlkF are average values
based on several hundred pressure fluctuation
values obtained in a given time period. The Diag
Period parameter is used to specify the sampling
period.
• Recalling the sampling period parameter (Diag
Period)
Recall
parameters
[Root menu] → Diag/Service → Diag
Parameters → ILBD Parameters →
Configuration → Diag Period →
The factory default setting is 180 seconds.
For details on situations that require the sampling
period to be changed, see subsection 7.3.2.2.10.
■ Diag Supp Count
Impulse line blockage is detected when values
such as Ratio fDP and BlkF exceed the threshold
consecutively several times. Diag Supp Count
defines the detection count.
• Recalling the detection count parameter (Diag
Supp Count)
Recall
parameters
[Root menu] → Diag/Service → Diag
Parameters → ILBD Parameters →
Configuration → Diag Supp Count →
If Diag Supp Count is set to 3, at point A in Figure
7.3.4, an alarm does not occur because the
blockage detection parameter (e.g., Ratio fDP)
exceeds the threshold only the first two times.
However, at point B in Figure 7.3.4, an alarm occurs
because the blockage detection parameter exceeds
the threshold three consecutive times.
