Maintenance/Troubleshooting - Detection problems
Intelli-FLEX II product guide • • • a - 7
3. Check the voltage on TP8 (sensor) to TP11 (GND). If it is less than 2 volts, the
sensor is probably defective. If the voltage is more than 3.5 volts, the sensor is
probably OK but there is a problem with the processor board.
Detection problems
The most likely causes for detection problems are discussed in this section along
with simple tests that can be made to locate and fix them. Lack of detection can be
caused by problems in three major areas:
•
sensor cable and sensor cable installation
•
processor parameter settings and adjustments
•
methods used to confirm detection
Sensor cable and installation problems
The Intelli-FLEX sensor cable is 100% pre-tested to a minimum sensitivity
specification at the factory. Although the cable is rugged, it can be damaged
during installation by applying excessive tension, or by kinking it.
Carefully follow the cable installation instructions
detailed in chapter 5. Do not over tighten the tie wraps.
Be sure to install drip loops at all junctions and splices
to help prevent water from getting into the cable.
If you are experiencing detection problems after properly installing the sensor
cable, check the following items:
1. Measure resistance between the center conductor and outer shield of the
female F-connector on the cable that attaches to the processor. Resistance
should measure between 950 K ohm and 1.05 M ohm. A resistance reading in
this range indicates good cable continuity and terminating resistance. If the
reading is outside this range the problem with the cable or terminating
resistor must be found and corrected.
2. Visually inspect all junctions and connections to insure they are well mated.
Be suspicious of any connection that is not “Perfect”.