E8500 Instruction & Operations Manual
version 1.017
Page 33 of 49
CHAPTER 10
CALIBRATION
Every instrument must occasionally be calibrated against some known value of a
parameter in order to make sure that its accuracy has not deteriorated.
Instrument calibration requires two steps. The first step is to zero the analyzer in a
clean, ambient temperature environment. The second step uses certified span gas
cylinders of known concentration to carry out a span calibration of the gas sensors.
The CALIBRATION MENU lets you set span calibration values for each sensor and
performs all sensor calibrations. The CALIBRATION MENU is shown below.
A brief explanation of the parameters shown follows below:
ZERO ALL SENSORS: This will set the zero point of
CO, CO
2
, HC, NO, NO
2
, SO
2
, H
2
S, VOC, and draft or
velocity values.
ZERO THERMOCOUPLES: This zeros the stack and
auxiliary thermocouples. The thermocouples must be at
room temperature when zeroing.
AUTOZERO ERRORS: This will display a list of sensors
that were out of the analyzer’s acceptable range during
the last autozero countdown.
SENSOR HISTORY: The date that each sensor was
installed is displayed, along with the date the sensor
was last calibrated and the span gas concentration
used.
T AMBIENT: Press the
OK
key to adjust the ambient
temperature reading. The display will show:
Amb Temp Offset: 0C
Use the
UP/DOWN
keys to set the value, in °C, to add or subtract to the displayed
ambient temperature.
T PREHEAT: This is the reading obtained from the second temperature input. It is
optionally used to measure the temperature of the preheat air, if preheat air is used
.
**** CALIBRATION ****
Zero All Sensors
Zero Thermocouples
AutoZero Errors
Sensor History
T ambient: 74 °F
T preheat: 74 °F
Zero Time: 60sec
Span Time: 120sec
** Span Lockout **
Span CO: xxxx PPM
Span H
2
: xxxx PPM
Span NO: xxxx PPM
Span NO
2
: xxxx PPM
Span SO
2
: xxxx PPM
Span H
2
S: xxxx PPM
Span CO-IR:xx.x %
Span CO
2
: xx.x %
Span HC: xx.xx %
Span Draft: xx "
