Yokogawa EJX930A - Manual (Page 153)

<Appendix 8. Advanced Diagnostics>
A8-9
IM 01C25T02-01E
Bit Alarm status
D
IA
G
_H
_
A
LM
D
IA
G
_L
_
A
LM
FL
G
_
TE
M
P_
A
LM
5 Low Side Blocking 
6 High Side Blocking 
7 B Blocking  
8 Invalid Ref BlkF  
9 Invalid Ref fSPh 
10 Invalid Ref fSPl 
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 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
FA0807.ai
Outside Diagnosis Range
Outside Diagnosis Range
 Invalid Ref BlkF, fSPh, fSPl, or fDP
This alarm indicates that the reference value under
normal condition is invalid. If REFERENCE_BLKF
is invalid, the blockage detection excluding VALUE_
BLKF is carried out. If blockage detection function
based on VALUE_BLKF is required, obtain the
reference value again.
Also when REFERENCE_DPAVG is below DIAG_
LIM [10] or exceeds DIAG_LIM [9], all reference
value becomes invalid so that “Invalid Ref fDP”,
“Invalid Ref fSPl”, “Invalid Ref fSPh”, and “Invalid
Ref BlkF” are generated.
A8.2.5.4 Alarm Masking
 DIAG_OPTION
The alarms linked to an analog alert and LCD
display are selected by DIAG_OPTION in the
SENSOR Transducer block. The BIT of DIAG_
OPTION is corresponding to that of DIAG_ERR.
To link the alarm to an analog alert and LCD display,
follow the procedure below.
1) Set "Stop" to DIAG_MODE.
2) Check each checkbox of the alarm, which is
selectable from bit 2 to bit 14.
Note: The bit 13 and 14 are used for Heat trace monitoring
function.
Set to “Calculation” after setting the parameters.