Teledyne M300EM User Manual

Page of 398
Teledyne API – Technical Manual - Model 300E Family CO Analyzers 
Calibration Procedures 
 
187 
9.1.2.2. Span Gas 
Span Gas is a gas specifically mixed to match the chemical composition of the type of gas being measured at 
near full scale of the desired measurement range.  It is recommended that the span gas used have a 
concentration equal to 80-90% of the full measurement range.  If Span Gas is sourced directly from a calibrated, 
pressurized tank, the gas mixture should be CO mixed with Zero Air or N
2
 at the required ratio. 
For oxygen measurements using the optional O
2
 sensor, we recommend a reference gas of 21% O
2
 in N
2
.   
  For quick checks, ambient air can be used at an assumed concentration of 20.8%.   
 Generally, O
2
 concentration in dry, ambient air varies by less than 1%. 
9.1.2.3. Traceability 
All equipment used to produce calibration gases should be verified against standards of the National Institute for 
Standards and Technology (NIST).  To ensure NIST traceability, we recommend to acquire cylinders of working 
gas that are certified to be traceable to NIST Standard Reference Materials (SRM).  These are available from a 
variety of commercial sources. 
Table 9-1:  NIST-SRMs Available for Traceability of CO Calibration Gases 
NIST-SRM TYPE 
NOMINAL 
CONCENTRATION 
1680b 
CO in N
2
 500 
ppm 
1681b 
CO in N
2
 1000 
ppm 
2613a 
CO in Zero Air 
20 ppm 
2614a 
CO in Zero Air 
45 ppm 
2659a
O
2
 in N
2
 21% 
by 
weight 
2626a CO
2
 in N
2
 4% 
by 
weight 
2745
2
 CO
2
 in N
2
 16% 
by 
weight 
1
 Used to calibrate optional O
2
 sensor. 
2
 Used to calibrate optional CO
2
 sensor. 
 
NOTE 
It is generally a good idea to use 80% of the reporting range for that channel for the span point 
calibration. 
For instance if the reporting range of the instrument is set for 50.0 PPM, the proper span gas would be 
40.0 PPM 
 
9.1.3. DATA RECORDING DEVICES 
A strip chart recorder, data acquisition system or digital data acquisition system should be used to record data 
from the serial or analog outputs of the M300E/EM.   
  If analog readings are used, the response of the recording system should be checked against a NIST 
traceable voltage source or meter.  
  Data recording devices should be capable of bi-polar operation so that negative readings can be recorded.  
  For electronic data recording, the M300E/EM provides an internal data acquisition system (iDAS), which is 
described in detail in Section 7.1 
 APICOM, a remote control program, is also provided as a convenient and powerful tool for data handling, 
download, storage, quick check and plotting (see Section 8.4). 
04288D DCN5752