Installation of High Pressure Sensor Replacement (PN: 502-107782) for Dr. Oligo 192

The purpose of this document it to show how to install the replacement high pressure sensor for pneumatic pressure on a Dr. Oligo plate instrument. The part number for this replacement sensor is 502-107782 - Switch Assembly, Pressure, 0-115 PSI, Dr. Oligo Plate (Link to website).  This sensor is replacing 506-103185 - Pressure Switch Assembly 0-125psi Includes Mount Bracket and Fittings (Link to website) when original sensor starts leaking.

This document will show how to correctly wire the new replacement sensor on the Dr. Oligo plate instrument. It will also show how to mount the sensor to the panel, using zip ties and the original sensor's bracket.

1. Make sure the instrument is powered off before proceeding.
2. Before removing spade connectors from the original sensor, take a picture of the originally wiring. Try to identify which connector is C, NO, and NC, then label each connector (if possible). This will make it easier to connect to the new sensor.
3. Remove the spade connectors from the original sensor. These spade connectors will directly attach to the connectors on the new sensor switch.
4. The wires on the new sensor switch are labeled with NO, NC, and C, along with a small description of which connector they connect to.
5. The black wire from old sensor will go to the black wire on the new sensor. However, you will have to determine which green wire goes where. Location of the wires are as follows:
   • NO - green wire going to the green LED
   • NC - green wire going to the red LED
   • C - going to black wire coming from sensor switch
6. When you remove the connectors from the old sensor switch, verify which green wire goes to the green LED and which green wire goes to the red LED.
7. Once you determine the location of the green wires, connect the wires from the old sensor switch to the new sensor switch accordingly.
8. After the wires are connected, power on the instrument. If you notice that the red LED is turning on when the green LED should be (or vice versa), your green wire connections are not connected properly. Swap the green wire connections to fix this.

1. Use zip ties to mount the sensor on the bracket used for the original sensor. It will be easier to position the sensor with the gas tube fitting down. Use zip ties to hold the sensor to the bracket (place the zip tie diagonally around the sensor and bracket).
2. Vent out the pneumatic gas and remove gas tube from the old sensor (will be either 1/8' tubing or 5/32" tubing). Then, place this tubing into the new gas tube fitting.
   • The fitting attached to the sensor fits 5/32" tubing, but there is an additional fitting for 1/8" tubing. If your instrument uses 1/8" tubing going into the sensor, replace the fitting with the 1/8" fitting.

1. The sensor is pre-adjusted to trigger the green LED at 95 PSI and trigger the red LED at 80 PSI.