Anderson LA Series Instruction Manual - Page 17

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3.4 TROUBLESHOOTING

As with any current loop, power supply and loop continuity are both imperative. If a problem

occurs, a methodical approach, beginning at the power supply is best.

3.4.1 Troubleshooting Steps

1. Measure power supply voltage across "loop+" and "loop-" terminals. Meter will read

between 12 and 40 VDC. (meter set to DC volts)

2. Disconnect one wire (+) from the signal receiver and install an accurate milliamp

meter in series with the receiver. The signal should correspond proportionally to the

height of liquid in the tank. (meter set to DC mA)

NOTE:

Above may differ if signal scaling is being done via microprocessor based

receiver. Product specific gravity values must be used in calculation.

3. If step 1 and 2 are satisfactory , the problem is with the receiver. (If supplied by

Anderson, refer to the instruction manual for that instrument).

4. Check all wiring connections between loop components. If OK, proceed to step 5.

5. With loop disconnected, the next step is to determine if there is a short to the

housing. This is accomplished by placing the (+) lead of the ohm meter on the loop+

terminal, and the (-) lead to the housing. The process should then be reversed. In

both cases, the meter should register infinite resistance. The process should then

be repeated on the loop- terminal of the sensor. Again, the meter should register

infinite resistance. If test is OK, proceed to step 6,

6. Wire transmitter independently of loop using two 9 volt batteries for power and

milliamp meter as a receiver. If signal is proper, approximately 4 mA with no product

on sensor, then problem is with external wiring.

NOTE:

Be sure to observe proper polarity as described in Figure 2-3

If any of the above indicate a transmitter problem, call your local distributor, or Anderson

Technical Service directly.

AGE