Yokogawa EJX930A - Manual (Page 59)

<4. Diagnostics>
4-9
IM 01C25R02-01E
4.2.2.3 Operation Parameters
 Diag Mode
Diag Mode gives the directive for the ILBD
operation. There are following three modes.
• Procedure to call up the display
DD (HART 5/7)
DTM (HART 7)
[Root Menu] → Diag/Service → Diag
Parameters → ILBD Parameters →
Configuration → Set Diag Mode →
DTM (HART 5) Diag and Service → Advanced Diag
Configurations → Impulse Line
Blockage Detection → Diag Mode →
Diag Mode
Mode Function
Stop The blockage detection operation is
stopped.
Calculation The blockage detection operation is
performed.
Alarms are generated along with the
result.
Reference Reference values for the blockage
detection are obtained and updated to the
latest. After sampling reference values,
this mode changes to "Calculation".
When the blockage detection operation is
performed, set “Calculation” to Diag Mode. “Stop”
must be set when you change a threshold value or
set an alarm. “Reference” is set in order to obtain
the reference fluctuation values under the normal
configuration.
NOTE
When setting ILBD parameters in the transmitter
via “Online Parameter” of the DTM (HART 5)
menu, Diag Mode automatically changes to 0
(Stop). After the setting, Diag Mode automatically
returns to the original value.
NOTE
When setting ILBD parameters in the transmitter
via “Download to device” of the DTM (HART 5)
menu, Diag Mode automatically changes to 0
(Stop).
 Diag Period
The values such as Ratio fDP and BlkF are
averaged based on several hundreds of pressure
fluctuation values in constant time. Diag Period
defines the sampling time is. The default value at
the shipment is set to 180 sec.
• Procedure to call up the display
DD (HART 5/7)
DTM (HART 7)
[Root Menu] → Diag/Service → Diag
Parameters → ILBD Parameters →
Configuration → Diag Period →
DTM (HART 5) Diag and Service → Advanced Diag
Configurations → Impulse Line
Blockage Detection → Diag Period →
For the information on how to change the sampling
period, refer to subsection 4.2.2.10.
 Diag Supp Count
When the value as Ratio fDP or BlkF exceeds
the threshold value for several times in a row,
it is estimated that the impulse line is plugged.
Diag Supp Count defines the number of times to
estimate blockage detection.
• Procedure to call up the display
DD (HART 5/7)
DTM (HART 7)
[Root Menu] → Diag/Service → Diag
Parameters → ILBD Parameters →
Configuration → Diag Supp Count →
DTM (HART 5) Diag and Service → Advanced Diag
Configurations → Impulse Line
Blockage Detection → Threshold →
Diag Suppress Count →
If Diag Supp Count is set to three times, an
alarm is not generated at part ‘A’ in Figure 4.4.
Because the first and second values only exceeded
consecutively the threshold.
When the value exceeds consecutively the
threshold value three times, an alarm is generated
(see part ‘B’ in Figure 4.4).