Yokogawa EJX930A - Manual (Page 158)

<Appendix 8. Advanced Diagnostics>
A8-8
IM 01C25R03-01E
A8.2.5 Alarm and Alert Setting
The abnormal results, as the blockage detection
and high/low flange temperature (heat trace
monitoring) are given by an analog alert or the LCD
display of alarm status. The analog alert or the LCD
display of alarm status is set according to the flow
shown in below figure.
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Discrete Alarm
FF Alert Notify and
(STB.FLG_TEMP_ALM)
Outside Diagnosis Range/
Invalid Ref xx
Masking
PV/SV/TV Status
Reflection Flag
(STB.DIAG_OPTION)
PV/SV/TV Status
Alarm Display
on LCD
Discrete Alarm
FF Alert Notification
(STB.DIAG_H_ALM)
(STB.DIAG_L_ALM)
Storage of Abnormal results
(STB.DIAG_ERR)
Alarm Masking
(STB.DIAG_OPTION)
Device Status
(RB.DEVICE_STATUS_7)
Alarm Enabling
(STB.ALAM_SUM.DISABLED)
Report Setting
(STB.DIAG_PRI)
Figure A8.5 Alarm and Alert Setting
 Alarm Status
When the algorithm of ILBD and Heat trace
monitoring detect the abnormality, the result is
stored in DIAG_ERR. The alarm status based on
the detected abnormality is displayed to DIAG_ERR
in the SENSOR Transducer block.
DIAG_ERR
Bit Alarm status
D
IA
G
_H
_
A
LM
D
IA
G
_L
_
A
LM
FL
G
_
TE
M
P_
A
LM
0 Not used.
1 Not used.
2 A Blocking
 
3 Large Fluctuation of Low Side 
4 Large Fluctuation of High Side 
5 Low Side Blocking 
6 High Side Blocking 
7 B Blocking  
8 Invalid Ref BlkF  
9 Invalid Ref fSPh 
10 Invalid Ref fSPl 
Bit Alarm status
D
IA
G
_H
_
A
LM
D
IA
G
_L
_
A
LM
FL
G
_
TE
M
P_
A
LM
11 Invalid Ref fDP  
12 Outside Diagnosis Range  
13 Flg Temp Low Alarm 
14 Flg Temp High Alarm 
15 Reflect Blockage to PV/SV/TV
status
Note: The bit 13 and 14 are used for Heat trace monitorig
function.
 Outside Diagnosis Range
1) dpavgmax
The dpavgmax, DIAG_LIM [9], is the upper
limit of the diagnostic capability range. The limit
value can be changed when DIAG_MODE is
“Stop”.
VALUE_DPAVG indicates the ratio of the
average of differential pressure to the EJX
maximum span regarded as 1. When VALUE_
DPAVG exceeds this limit, “Outside Diagnosis
Range” is generated so that the blockage
detection becomes impossible.
2) dpavgmin
The dpavgmin, DIAG_LIM [10], is the lower
limit of the diagnostic capability range. The limit
value can be changed when DIAG_MODE is
“Stop”.
When VALUE_DPAVG is below this limit,
“Outside Diagnosis Range” is generated so that
the blockage detection becomes impossible.
<Example>
When the level range that can be measured by the
transmitter with 100 kPa span is -80 to 80 kPa, the
limits are set as follows.
• dpavgmax: 0.80
• dpavgmin: -0.80
1.000
0.000
0.80
-0.80
-1.000
Detectable
range
DPAvg
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Outside Diagnosis Range
Outside Diagnosis Range