RLE GD100 User Manual
Page 15
CTS-M17 Installation, Operation and Maintenance Manual
B84450-001-000 RG
May 12, 2005
14
Note: When changing the gas type, the unit must be re-calibrated
to the selected gas type and concentration.
9.
Auto-zero
When the Auto-zero function is enabled the unit will perform an automatic
zero calibration of it’s reading. It does this by maintaining a record of the
lowest reading observed in the last 8 days and then assigning that as the
new zero gas base line. This is subject to overriding measures of sensor
failure. In addition, if the drift has been more than negative 5% of the LEL,
then the unit will flash “AUTOZERO”
A
A
U
U
T
T
O
O
Z
Z
E
E
R
R
O
O
E
E
n
n
a
a
b
b
l
l
e
e
This menu item has options:
Enable
Disable
Clear
Clear resets the Auto-zero setting. This should be done after every
calibration.
Note: Selecting “Clear” will clear the 8-day auto-zero timer and
automatically enable auto-zero. If you want auto-zero
disabled after clearing the auto-zero timer, go back into
AUTOZERO and select “Disable”.
10.
Calibration
Calibration is done with potentiometers on the circuit card, not through the
menu system, and so it is possible to perform the adjustments without the
menu system; however, the menus do offer increased display resolution,
and disabling of output actuation.
C
C
A
A
L
L
I
I
B
B
R
R
0
0
1
1
0
0
.
.
5
5
%
%
Entering this menu item only displays the concentration with 0.1%
resolution for more accurate calibration. Reading is in %LEL, even though
only % is displayed.
Calibration Procedure:
Response of this sensor to gas is quite rapid, and the signal should be
adequately stable for adjustment in less than one minute. It is best to allow
one hour warm-up and stabilization time before calibrating.