•  OS-4 Manual

Support Related
Frequently Asked Questions

• Q.What happens if the monitor is used in temperatures above 104F?

  A.Because this monitor utilizes a Heated Metal Oxide Semiconductor (HMOS) to detect ozone, high ambient temperatures could likely push the sensor-heater above its safe operating temperature, causing permanent damage.

• Q.On the OS-4, why is my Analog Output reading 1/2 of the Display reading? (For example, the OS-4 analog output seems to indicate 0.2 ppm when the OS-4 display reads 0.4 ppm)

  A.This discrepancy is due to the Scaling of the Analog Output (and applies to both the 4-20 mA and 0-2V outputs). The OS-4 utilizes an SM-X sensor. This chip, on its own, is designed to read up to 20 ppm. Therefore the output of the chip scales from 0-20 ppm, even though the OS-4 is rated for just 0-10 ppm. If your analog readings are 1/2 of what is diaplayed, it is likely because you scaled your analog output from 0-10 ppm instead of 0-20 ppm. As an example, if your OS-4 is reading 10 ppm you may expect to see 2V on the analog output (full scale). Instead, you will see 1V (1/2 scale). This is because the analog output scales to the full 20 ppm range of the SM-X sensor chip, meaning that a 1V reading corresponds to 10 ppm. The correction is to scale your analog output from 0-20 ppm (4-20 mA output or 0-2V output).

• Q.What is the scale of the 4-20 mA output?

  A.The scale of the 4-20 mA output is 0-20 ppm, as follows: 4 mA = 0 ppm, 20 mA = 20 ppm

• Q.What is the scale of the 0-2V mA output?

  A.The scale of the 0-2V output is 0-20 ppm, as follows: 0 V = 0 ppm 2 V = 20 ppm