MAN-0148, Rev 1
27
March 2016
4.2.1 Full calibration (Normal calibration) procedure
Prior to attempting calibration read and understand the calibration procedure below. Also see
Figure
18 for additional reference.
The following calibration procedure should be followed to ensure an accurate correlation between the output signal and
the gas concentration. For accurate performance, the Millennium II is calibrated using 50% span gas. The transmitter will
however, allow some flexibility in the use of calibration gas with some sensors; calibration gas outside of 50 % span (10% -
60% span gas) will be allowed on specific sensor models (see specific sensor manual for details). The calibration gas value
can be chosen by selecting it under
“cal. gas value”
in the main menu. A full calibration will take approximately 5 minutes to
complete.
Ensure the transmitter is functioning properly as indicated by the status LED and current output.
1.
Enter the main menu by selecting/activating any key to get the
“enter main menu”
prompt, then activate
switch 1
to select
“yes”
.
2.
When
“Calibrate Sensor?”
is displayed, activate the enter key (
switch 3
).
3.
When
“Calibrate Sensor #1?”
is highlighted, activate the enter key (
switch 3
) if this is the sensor to be calibrated.
4.
If sensor #2 is to be calibrated, select the down arrow key (
switch 2
) to scroll to
“Calibrate Sensor #2?”
5.
Select the desired sensor to be calibrated (1 or 2) by activating the enter key (
switch 3
).
6.
Select
“YES”
with
switch 1
to confirm the selection, and then apply clean air (zero gas) from canister when
“Apply
Clean Air
” is displayed. Ensure no contaminant gases are around if ambient air is being used.
7.
Select “
Z & Span”
using
switch 1
for normal (full) calibration.
“Setting zero”
will be displayed as the sensor is being
zeroed.
8.
Apply 50% calibration gas (* or
%
cal. gas value
chosen) when prompted.
9.
The display will show
“Spanning”
with the gas value (%LEL or PPM depending on the sensor) as the gas is
detected.
10.
Remove the calibration gas when
“Remove Cal Gas”
is displayed.
11.
“Cal Complete”
will be displayed when calibration is complete.
12.
Apply zero gas (clean air) to purge system. This is particularly important when using long tubing.
* Note: Selectable calibration gas value (% cal. gas value) is only available for some sensor types.
Warning
Always apply test gas after any calibration to verify accuracy; do a bump test after calibration. When
applying test gas, make sure the system is bypassed to avoid unwanted shutdowns.