Chapter 4 ________________________________________________________________ Operation
VAISALA____________________________________________________________________ 55
Syntax: PURR x<cr>
where
x
= ON/OFF (default = OFF)
NOTE
When you enable this function, wait about 8 min after powerup
before taking measurements. The powerup chemical purge locks the
output values for the first operation minutes.
Chemical Purge Activated Manually
Chemical purge needs to be performed always before calibration (see
Calibration and Adjustment on page 64) or whenever there is reason
to believe that the sensor has been exposed to an interfering chemical.
Make sure that the temperature of the sensor has come down to
normal before starting calibration.
Before starting chemical purge please note the following:
- The sensor is protected with a PPS grid with stainless steel netting,
a stainless steel sintered filter or with a membrane SST filter.
- The sensor temperature needs to be below 100 °C. At higher
temperatures the chemicals evaporate spontaneously from the
sensor and the chemical purge is not necessary.
Starting Manual Chemical Purge
Type PURGE via the serial line to activate chemical purge.
Syntax: PURGE<cr>
>purge
Purge started, press any key to abort.
>
The prompt ">" appears when the heating period is over. However, the
transmitter outputs are locked to values measured before chemical
purge until the settling time is over.
