Firmware

The ozone sensor board in the SM70 is factory set to one of three firmware versions to control the relay and alarm functionality:

• Alarm above (AA). The relay is energized when the reading is above the set point.
• Alarm below (AB). The relay is energized when the reading is below the set point.
• Control 10% (C10). The relay is energized to control the gas concentration to a band within +/-10% of the set point.

You choose which firmware you want when you order your SM70. The firmware version is indicated on a label under the lid.

The relay has COM (common), NO (normally open) and NC (normally closed) contacts.

The relay is programmed to energize above the selected set point. Typical applications are health and safety alarm/warning systems or switching external equipment on and off.

Note: This is the default firmware version.

• When the gas concentration is rising from below the set point, the relay is de-energized (relay NO=open, NC=closed).
• When the gas concentration rises and reaches the set point, the relay is energized (relay NO=closed, NC=open).
• When the gas concentration drops and reaches the set point, the relay is de-energized (relay NO=open, NC=closed).

The relay is programmed to energize below the selected set point. Typical applications are fail safe warning systems or controlling a gas generator.

• When the gas concentration is rising from below the set point, the relay is energized (relay NO= closed, NC=open).
• When the gas concentration rises and reaches the set point, the relay is de-energized (relay NO=open, NC=closed).
• When the gas concentration drops and reaches the set point, the relay is energized (relay NO=closed, NC=open).

The relay is programmed to open and close around the selected control set point ±10% to create a control band.

A typical application is maintaining a specific gas concentration between user-defined levels through the control of an external device, e.g. ozone generator.

• When the gas level is rising from below the lower limit to the upper limit, the relay is energized, (NO=closed, NC=open).
• When the gas level is falling from above the upper limit to the lower limit, the relay is de-energized (NO=open, NC=closed).