Teledyne API M452 Ozone Sensor Instruction Manual, 02852, Rev. E
5-1
5 Sensor and System Troubleshooting
This chapter gives guidelines for diagnosing system and sensor
malfunctions using the four digital Status Outputs provided by the M452.
All troubleshooting should be done after the M452 has been turned on and
allowed to warm up for at least 15 minutes.

5.1 Status LED’s

On the top of the M452 are five status LED’s.
The Status LED labeled ‘CPU STATUS’ is used to verify the status of the
CPU inside the M452. This LED should blink on and off continuously
while the sensor is on. If this LED stops blinking while power is applied
to the sensor, a CPU failure is indicated.
The other four Status LED’s on the M452 exactly mirror the four Status
Outputs described in the following sections.