Test of SLX 130-M mA draw

The general operation of a SLX 130-M may be easily tested in the field.

You will need a 9 VDC battery, a mA meter and 3 test leads (the photo shows a red, a black and a white test lead).

(Make sure its a SLX 130-M - a heat shrink label at the end of the signal cable indicates the sensor version.)

Connections:

1. +VDC of the 9 VDC battery to the Red (+) lead of the mA meter
        (photo shows a red test lead w/ alligator clamps).

2. Black (-) lead of the mA meter to the Red signal wire of the SLX 130-M (photo shows a white test lead).
3. Black signal wire of SLX 130-M to -VDC of 9 VDC battery (photo shows a black test lead).

Make the above connections directly to the signal wire. The goal is to ensure the proper operation of the sensor to quickly debug the system.

After making the above connections, the general operation of the sensor may be verified by pressing lightly on the diaphragm. (Reference note 1 below.)  The SLX 130-M transmits a nominal 4-20 mA over its rated pressure range.

Common installation errors include:

1. Resting the SLX 130 on the bottom of the sump pit.  Sludge may press on the diaphragm and elevate its mA output.
2. Reversal of leads.  The SLX 130-M is polarity sensitive and will not operate when the leads are reversed.
3. Ground loop.  A portion of the 4-20 mA loop may be accidentally grounded.  Inspect all wire terminations to ensure there are no loose strands touching other wires or are shorted to ground.

Note: 1 - It is possible to raise and lower the sensor in water or the sensed media.

         2 - The white "signal" wire is not used.

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