AMX Power Current Sensors PCS - Manual (Page 13)

Calibration
9 PCS and PCS2 Power Current Sensors
PCS2 Calibration
When extreme accuracy is required for calibration, allow the PCS2 to warm up for a minimum of
15 minutes before calibration. The following procedures are used for both circuit 1 and circuit 2.
Calibrate each circuit independently.
If the device only has an ON state, either STANDBY or ON can be used in the following steps.
1. Plug the PCS2 into a power source.
2. Connect the device.
3. Turn both POTS all the way counter clockwise. At a maximum, this is 20 full turns. The stop
(end) can be detected by a subtle clicking sound and feel.
4. Set the device to the STANDBY power mode and wait 2-seconds. STANDBY power mode is
obtained by plugging the unit into an electrical port and not turning the power switch ON.
5. Turn the PCS2 STANDBY POT clockwise until the STANDBY LED lights.
6. Slowly turn the POT counterclockwise until the LED goes out. Then, very slowly turn the POT
clockwise until the LED lights. The "turn-on-threshold" has just been determined. It is best not
to set precisely on this threshold, so turn the POT a fraction more clockwise. This fractional
extra turn can be a bit larger for higher power devices and may be almost negligible for very
low power devices.
7. Turn the devices off and wait 2 seconds.
8. If the LED is still on, repeat steps 6 through 8 until the LED is not on when the device is turned
off.
9. Perform steps 1 through 8 for the ON circuit level.
10. Repeat steps 1 through 9 for the second PCS2 circuit's STANDBY and ON circuit levels.
Because of hysteresis (the analog circuit components time for changing states) the
turn-on and turn-off thresholds will not be exactly the same.