The battery-operated instrument also runs a self-test of the sensor immediately after switch-on, thus ensuring the operator is aware of the instrument’s status via an acoustic confirmation of readiness for measurement.

Once gas is detected, the testo 317-2 increases the alarm volume as the level of gas detection increases, and emits a permanent signal when the alarm limit is exceeded.

The instrument has an automatic zeroing phase when the device is switched on in fresh air.