Test Equipment: Feedback Transducer Tester
Basic Test Procedure for All Digital and Analog Sensors |
Display Interpretations for Troubleshooting
Basic Test Procedure for All Digital and Analog Sensors
The following is the basic procedure for all digital and analog sensor models.
- Determine model of the sensor, operating voltage and its inputs and outputs.
- Using the correct hookup drawings, connect the sensor to the header connector. Labeling is provided on the front of the panel next to each test header for easy signal orientation. Plug the connector to the appropriate test header on the TTU-2.
- Verify correct connections to sensor power.
- Verify connections:
- DIGITAL connecter: Verify Interrogation and Gate polarities are correct.
- ANALOG connecter: Verify the polarities of voltage and current connections and the associated returns are correct.
- SSI/485 connecter: Verify 485, data and clock polarities are correct.
- Plug in power to the TTU-2.
- Turn on power to the TTU-2.
- The TTU-2 LCD display will show a splash screen for 3 seconds. The screen shows program version and date at the bottom of the display.
- After the initialization and self-test, the TTU-2 Main Menu is displayed, listing the sensor models that can be tested.
- Enter the number associated with the sensor model you want to test via the keypad.
- Follow the instructions shown on the display. The menus will guide you through the test setup.
- Once you have configured the test options for the sensor under test, the test begins automatically.
- Move a magnet along the housing. The display will show position relating to magnet position.
- If the sensor fails the test, or the connections are not correct, a Sensor Not Responding Screen appears.
- If the sensor fails, the user can check the connections to the TTU-2 and press <ENT> to repeat the test using the same test setup. Pressing the <CLR> key returns to the main menu.
Note: R-Series SSI and S-Series Sensors require supply voltage (+24vdc) to be cycled for sensor programming. Sensors connected to the SSI/485 header have operational voltage switched ON by the TTU-2 at test/programming time. Any sensors connected to the DIGITAL and ANALOG headers will have operational power applied as soon as power is turned on.
Figure 5 - Sample Run Screen
Figure 6 - Sample Sensor Not Responding Screen
Display Interpretations for Troubleshooting
- If the TTU-2 is displaying a position on a Run Screen:
- Slowly move the magnet through the full stroke length of the sensor. Observe the display as the magnet is moved.
- If the displayed position stops changing but continues to show a steady position, repair or replacement is needed.
- If the Sensor Not Responding Screen appears, the sensor has a dead spot, and repair or replacement is needed
- Sensors have a 2.5” dead band at the tip end of the pressure housing. Observe the display as the magnet is moved toward the tip end of the sensor, but before the 2.5” dead band is reached.
- If the displayed position stops changing but continues to show a steady position, repair or replacement is needed.
- If the Sensor Not Responding Screen appears, the sensor has a dead spot, and repair or replacement is needed. Pay particular attention to the magnet position while testing the sensor at the tip end. The Sensor Not Responding Screen will appear when you hit the dead band.
- Gently move the connector and/or cable connection to the head cap while observing the displayed position. If the position freezes or a Sensor Not Responding Screen is shown, the sensor needs repair. Please note: the object is to confirm a solid connection to the sensor, so exert little or no force while testing the connector and/or cabling.
- While holding the magnet steady, lightly tap the housing and observe the position on the display. (Use a small screwdriver, and tap no harder than you would tap on the back of your hand). If the position jumps significantly or a Sensor Not Responding Screen appears, the sensor has problems with the waveguide or sensor pickup and needs repair.
- If the Sensor Not Responding Screen appears (no Run Screen is displayed):
- Check the connections to the TTU-2 headers. If the connections are correct then sensor repair or replacement is needed.
- Gently move the connector and/or cable connection to the head cap while pressing <ENT> to repeat the test with current settings. If a Run Screen is displayed, the sensor connector/cabling needs repair. Please note: the object is to confirm a solid connection to the sensor, so exert little or no force while testing the connector and/or cabling.
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