3XXX Pressure Sensors: Ratiometric Output Testing
- This bench test applies only to sensors with a Ratiometric output.
- This is indicated by the T in the part number, highlighted in yellow.
When you are troubleshooting an issue with your sensor or device, we strongly recommend completely removing it from your system to bench test it. Many times, the consumer's wiring/PLC/controller can incorrectly influence the testing circuit and adds variables to your testing. The method below reduces as many variables as possible to allow you to Bench Test your sensor and ensure it is working OK. If there is an error in the wiring or controllers, this will attempt to remove them from the equation.
Preparation
- Remove the sensor from your system completely.
- If that is not possible, then only electrically remove it from your system.
- Make sure your power supply and multimeter are off.
- Download the 3100 Series Instruction Bulletin for reference.
- Reference the pinout chart for three pins/wires used in the voltage output:
Basic Wiring Diagram
See below:
Components for the Bench Test
- Known good Power Supply capable of producing 5.0 VDC. It is very important to have exactly 5.0 VDC.
- See write up on Ratiometric Sensors.
- Known good Multimeter, set to measure DC Volts (READOUT).
- Appropriate mating electrical connectors or jumpers (if needed).
Wiring your Bench Test Setup
- From your Power Supply, connect a wire from the (+/RED) connection to the VSUPPLY input on your sensor.
- From the (-/BLACK) connection of your Power Supply, connect a wire to the Ground/Common connection of your sensor.
- Also from the (-/BLACK) connection of your Power Supply, connect a wire to the (-/BLACK) connection of your handheld Voltmeter (READOUT).
- From the (+/RED) side of your Voltmeter, connect a wire to the Vout1 (or Vout) connection of the sensor.
- Do not connect anything to the other unused wires/pins of your sensor.
Gotcha’s
- Make sure you have NOTHING else connected to this circuit. This will eliminate any variables in the test.
- Make sure your Multimeter is set to VOLTS. Not Amps or Ohms.
- Make sure your probes are in the correct holes of the Multimeter to read VOLTS or VOLTAGE. Some meters have one connection for amps and one connection for volts/ohms.
- If your meter is not Auto-ranging, then set it to read in the 0 thru 5 or 0 thru 10 VDC range.
- If you are using a mating connector, pay attention to the Pin callouts. They are opposite on the sensor versus the harness so when you connect them, they line up correctly.
- For example, the Packard pinouts:
The sensor side looks like this:
The harness looks like this (colors may vary):
You can see the A and B pins are opposite in the two pictures.
You are now ready to start the BASIC Bench Test
This will give you a simple health check of the sensor to make sure it has an output.
- Double check all wiring.
- Turn on the Multimeter, set to the Voltage range.
- Turn on your Power Supply. As per above, set it to exactly 5.0 VDC.
- With no pressure on the sensing port of the sensor, you should see 0.5 VDC (or 500 mV DC) plus or minus a small error Zero Tolerance error.
- The Zero Tolerance error spec for the 3100 is 0.5% of Span.
- Span is 4VDC (4.5V less 0.5V).
- If you see any output that is greater than 0.52 VDC or less than 0.48 VDC, you might have a bad sensor. If it is in that range, then you are OK.
- Turn off the Power Supply and Multimeter.
If you have a pressure source available, you can perform the ADVANCED Bench Test
This will allow you to check the sensor at pressure.
- Connect to a known reliable and accurate pressure source. Be careful when high pressure is involved.
- Turn on the Multimeter.
- Turn on your Power Supply, set it to 5.0 VDC.
- Repeat the Basic Bench Test: With no pressure on the sensing port of the sensor, record the Voltmeter reading. This is your Zero Point value.
If you find that your sensor is not reading correctly, contact Gems with your part #, PO #, findings and for next step options.