24
SYMPTOM
PROBLEM
ACTION
Change in pH slope (value
1. Old or coated glass electrode.
1. Clean or replace glass electrode.
decreasing to 49.0 or less).
2. Bad RTD value.
2. See
Table 8-2
with RTD resistance
and temperature values.
pH value locks up (no change
1. Glass electrode cracked.
1. Replace glass electrode.
of reading in different buffers).
(if value stays at 6.5-7.0 pH)
2. Clean glass electrode.
2. Coated glass electrode.
2081 pH value not the same
1. Grab sample incorrect.
1. Re-evaluate sample technique
as grab sample of process.
and equipment.
2. Unclear what is correct.
2. Test with buffer solution.
3. 2081 pH out of calibration.
3. Recalibrate per start-up and
calibration section.
Fault code “
tEnP-Lo
” or
1. Miswire.
1. Check wiring between the sensor
“
tEnP-Hi
”.
and the transmitter.
2. Open or shorted RTD.
2. Replace RTD or sensor.
3. Manual temperature mode.
3. Appropriate resistor must be
in place TB1-6 & 8. See
Table 8-2
.
Fault code “
SLP-FAIL
”.
1. Coated electrode.
1. Clean or replace electrode.
2. Improper buffer calibration.
2. Recheck buffer accuracies.
Change slope value (SLP) to 59.1
3. Defective electrode.
3. Replace electrode.
4. Plugged liquid junction.
4. Replace liquid junction.
Fault code “
rngE-LOOP
”.
1. Process value is outside.
1. Return process to normal.
4-20 mA range points.
Check grab sample.
Fault code “
FAIL
”.
1. Input signals are invalid.
1. Toggle Power
2. Calculation is invalid.
2. Change slope value (SLP) to 59.1
3. Defective PCB stack.
3. Perform a complete bench check
to try to clear the error.
No output current.
1. Defective PCB stack.
1. Replace PCB stack.
2. Miswire.
2. Check for short.
Low output current.
1. Circuit loading with excessive
1. Consult output loading limits
resistance on output .
2081 pH specifications (1840 ohms
max load).
“
inPt
” in display submenu reads
1. Junction poisoning.
1. Replace junction or sensor.
increasingly greater or less than
0 mV at 7.00 pH.
Fault code “
LOOP
” flashing
1. Model 268 or other host has
1. Model 268 or other host can
intermittently with pH and
set the output to a specific value.
return transmitter to normal
output value.
operation.
Fault code “
SnSr
-
FAIL
1. mV input exceeds ±675mV or
1. Check wiring; toggle power.
RTD resistance is over 600 .
2. Perform a complete bench check.
2. A-D failure
3. Replace PCB stack.
TABLE 8-5. Troubleshooting Guide
MODEL 2081 pH
SECTION 8.0
DIAGNOSTICS AND TROUBLESHOOTING
Содержание 2081 pH
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