TPS miniCHEM-pH - Troubleshooting

Page 19
9. Troubleshooting
9.1 Instrument Function Troubleshooting
Symptom Possible Causes Remedy
No display 1. Mains power input not
switched on.
2. Mains power input
incorrectly connected.
3. Instrument is faulty.
Switch power ON.
Check connections (see section
3.4).
Return to TPS for repair.
Alarm LED or
(optional) relay
output do not
operate when limit
is exceeded.
1. Limit not set correctly for
“too high” or “too low”
alarm/control.
2. Optional relay output not
fitted.
3. Hysteresis too large.
4. Fuse has blown.
5. Instrument is faulty.
Set the Lo/Hi Output jumpers
correctly (see section 3.5.2).
Return unit to factory to have
relay output fitted (part no
130342).
Check and adjust the
HYSTERESIS trimmer (see
section 3.5.3). If in doubt, set
this to minimum level.
Check and replace fuse if
necessary (see section 8).
Return to TPS for repair.
Incorrect analogue
output signal.
1. Current/Voltage Output
jumpers incorrectly set for
required output.
2. 4-20mA loop resistance too
high.
3. Load on 0-1V DC output is
too low.
4. 4-20mA output is not
calibrated.
5. Instrument is faulty.
Check that the Current/Voltage
Output jumpers are correctly
set for 4-20mA or 0-1V, as per
requirements. Adjust if
necessary (see section 3.6).
Ensure loop resistance does not
exceed 500 Ohms.
Ensure load is 1000 Ohms
minimum.
Calibrate 4-20mA output (see
section 3.7).
Return to TPS for repair.