Troubleshooting - Suspended Solids Monitor Model 950
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| Problem | Possible Cause | Check/Remedy |
| Meter indication is blank | • No power • Blown fuse • No power to instrument • Faulty transmitter/indicating meter |
• Check power light. • Check fuse. • Check for proper voltage on terminals 8 & 9. • Refer to supplier. |
| Meter will not zero (high reading) | • Too much absorbed light
• Poor sensor connections or incorrect wiring • Sensor leads not insulated from body of sensor or conduit • Wet connection in converter or sensor housings • No power to sensor • Faulty sensor bulb or defective sensor/transmitter |
• Remove sensor and place in clean
water. If the meter does not zero
then try adjusting CS (course zero)
on the circuit board.
• Check connections and wiring. • Check sensor wires. • Look for water or condensate on connections. • Voltage should be 7-10 VDC between terminals 5 and 6 on the main circuit board. Also, there should be 6-9 VDC on terminals 5 and 6 of the circuit board in the sensor. • If the proper voltage (8-11 VDC) is on terminals 5 and 6 and the bulb in the sensor is not on, then the bulb has failed. |
| No response (indication does not change and indication is high) | • Faulty sensor bulb | • Check to see if sensor lamp is on. If lamp is off, check voltage across terminals 5 & 6 in sensor. If the proper voltage (8-11 VDC) is on terminals 5 and 6 and the bulb in the sensor is not on, then the bulb has failed. |
| Unstable reading | • Insufficient dampening
• Air bubbles or very large particles in process line • RFI pickup • Heavy inductive loads |
• Increase dampening.
• Take sample and check for bubbles or large particles. If present, relocate sensor. • Earth ground instrument properly. • Mount instrument away from power cables. Put cables in conduit. |
| Reading does not agree with lab results | • Improper calibration • Lab procedure error • Lab instrument error • Defective sensor |
• Recalibrate instrument. • Check procedure. • Check instrument. • Refer to supplier. |
| Readings drift with time | • Converter not warmed up • Sensor/converter connections wet • Deposit buildup on sensor |
• Warm up converter for 15 minutes.
• Look for water or condensate on connections. Dry connections with hair dryer. • Remove sensor and clean. |
| Negative readings or negative output | • Improper calibration | • Recalibrate instrument. |
