Here are the instructions with a video for calibrating the GPL Z9000 natural gas odorizer’s optical comparator. If you are looking for instructions for the GPL 750 odorizer, see optics calibration.
The optical comparator and optical arrays use fiber optics to count the odorant drops as they drop through the drip chamber and into the line. It is this precise counting of measured drops that permits accurate injection.
The optical array on one side of the drip chamber conveys a beam to the array on the other side. When the beam strength suddenly changes, the comparator registers a drop and sends a signal to the Mixed I/O control board.
There are three lights in the comparator.
- Green – Comparator is powered (this is always on)
- Red – The arrays are locked onto each other (this is always on)
- Yellow – A drop has fallen. If there is more or less than one blink per drop, calibrate the comparator.
A couple of fiber optic lines run from the optical comparator to the arrays, one on each side of the drip chamber. Exercise care and do not damage or interfere with the wires.
Calibrating the Optical Comparator
Before the GPL Z9000 is shipped, the optical comparator is calibrated at the factory. If it is not operating as programmed, use the following calibration procedure.
- Observe the odorant drops through the sight glass below the metering valve.
- As each drop falls, watch the yellow light on the optical comparator. If the yellow light:
- Does not blink; turn the gain clockwise until it blinks. (The gain is the signal strength on the optical comparator, turning up the gain raises the signal strength, turning down the gain lowers it).
- Flickers once (solid); it is calibrated correctly.
- Flashes many times (flickers), turn the gain counterclockwise until it stops flashing, then turn clockwise twice.
- Continue watching and adjusting the gain on the optical comparator until the yellow light blinks once per drop.
Refer to the following video on calibrating the optical comparator and validating the odorant drop count.
Download the GPL Z9000 User’s Manual.
You can see other TechView videos for the Z9000 here.