Riken Keiki GD-84D-EX Series, Operating Manual

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6. Alarm Activation 6-4 Various functions to ensure proper alarm activation
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6-4 Various functions to ensure proper alarm activation
6-4-1 Zero suppression function
The sensors incorporated into the product are susceptible to fluctuations in ambient conditions (e.g.,
temperature and humidity characteristics) and interference gases (interference characteristics). These can
affect readings. This means readings may fluctuate around zero levels even under normal conditions.
The zero suppression function is designed to minimize the effects of these ambient fluctuations and
interference gases around the zero level. Use this function to suppress fluctuations in readings of less
than the preset value to give zero readings (or [20.9] (vol%) for oxygen).
For example, HF readings will be indicated as follows:
<Zero suppression function disabled> <Zero suppression function enabled>
The reading fluctuates around zero. Displays zero up to the standard setting value
(6 % F.S. (0.09 ppm))
NOTE

The standard preset value for the zero suppression function differs depending on sensor
specifications.

This function is disabled in maintenance mode. Fluctuations in readings of less than the value set
are displayed.

When an oxygen deficiency alarm model sensor (ESF-X24P: 0 - 25 vol%) is fitted, the zero
suppression function works on the atmosphere (20.9 vol%), which is the normal value. In this case,
if readings fluctuate near 20.9 vol%, the reading displayed is [20.9] (vol%) (AIR suppression).
CAUTION

The negative suppression value (below zero) is subject to suppression corresponding to 10 % of full
scale. If the value below zero becomes 10 % of full-scale or larger, the reading will be displayed as
[-0.0], and accurate gas detection will not be possible in this state. Perform zero calibration.