Teledyne GFC 7001E, GFC 7001EM 9.1.3. DATA RECORDING DEVICES

Calibration Procedures Model GFC7001E Carbon Dioxide Analyzer

Teledyne Analytical Instruments 187

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 N2 at the required ratio.

For oxygen measurements using the optional O2 sensor, we recommend a reference gas of 21% O2 in N2.

 For quick checks, ambient air can be used at an assumed concentration of 20.8%.

 Generally, O2 concentration in dry, ambient air varies by less than 1%.

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 N2 500 ppm

1681b CO in N2 1000 ppm

2613a CO in Zero Air 20 ppm

2614a CO in Zero Air 45 ppm

2659a1 O2 in N2 21% by weight

2626a CO2 in N2 4% by weight

27452 CO2 in N2 16% by weight

1 Used to calibrate optional O2 sensor.

2 Used to calibrate optional CO2 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 GFC 7001E/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 GFC 7001E/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).