Teledyne 2000XTC - Thermal conductivity analyzer - Manual (Page 30)

Installation 2000 XTC
zeroing this instrument when using a gas different than the
gas specified at the time of purchase.
To zero calibrate this instrument:
1. Connect a read-out device to the 4-20 mA output signal
terminals on the galvanic isolator module according to
Section 3-5.
2. If the transmitter cover has not been removed, unscrew the 4
cover screws and remove the top cover.
3. Allow zero gas to pass into the transmitter. The pressure
should be regulated between 2-20 psig and the flow set
between 0.4 –2 SCFH.
Note: It may be necessary to purge the sample line and
transmitter with zero gas for several minutes before
obtaining a stable zero reading.
4. The output should read the zero gas value or 4 mA. If not,
adjust the zero potentiometer (R8) on the PC board using a
thin blade screwdriver until the reading is the zero gas value
or 4 mA.
5. It may be necessary to recalibrate the zero after span
calibration.
3.6.3 Span Calibration
Span calibration requires the use of a prepared gas mixture
containing a known concentration of the gas species to be analyzed in a
background gas. An acceptable span gas concentration is 70-100% of
the anticipated analysis range.
Note: This instrument was assembled and calibrated at the
factory using a specific gas mixture determined at the time
of purchase to be representative of the customer’s
application. Specific data has been pre-programmed into
the transmitter that is used by the system to linearize the
output signal generated by the sensor. If a different gas is
used, the resulting output signal may not be linear with
concentration. You also may experience difficulty in span
calibrating this instrument when using a gas different than
the gas specified at the time of purchase.
Teledyne Analytical Instruments 20