Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 191)

Calibration Procedures Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 173
7.5.2. Use of Zero/Span Valves with Remote Contact Closure
Contact closures for controlling calibration are located on the rear panel CONTROL IN connector.
Instructions for setup and use of these contacts are found in Section 6.15.1.2. When the contacts are
closed for at least 5 seconds, the instrument switches into zero or span mode. The remote calibration
contact closures may be activated in any order. It is recommended that contact closures remain closed
for at least 10 minutes to establish a reliable reading.
The instrument will stay in the selected mode for as long as the contacts remain closed. If calibration is
enabled, the GFC 7000TA will re-calibrate when the contact is opened, then go into SAMPLE mode. If
calibration is disabled, the instrument will return to SAMPLE mode, leaving the calibration unchanged.
7.6. Automatic Zero/Span Cal/Check (AutoCal)
The AutoCal system allows unattended periodic operation of the ZERO/SPAN valve options by using the
GFC 7000TA’s internal time of day clock. AutoCal operates by executing SEQUENCES programmed by
the user to initiate the various calibration modes of the analyzer and open and close valves appropriately.
It is possible to program and run up to 3 separate sequences (SEQ1, SEQ2 and SEQ3). Each sequence
can operate in one of 3 Modes, or be disabled.
Table 7-1: AUTOCAL Modes
MODE NAME ACTION
DISABLED Disables the Sequence
ZERO Causes the Sequence to perform a zero calibration/check
ZERO-SPAN Causes the Sequence to perform a zero and span concentration
calibration/check
SPAN Causes the Sequence to perform a span concentration
calibration/check
For each mode there are seven parameters that control operational details of the SEQUENCE. They are:
Table 7-2: AutoCal ATTRIBUTE Setup Parameters
ATTRIBUTE NAME ACTION
TIMER ENABLED Turns on the Sequence timer
STARTING DATE Sequence will operate after Starting Date
STARTING TIME Time of day sequence will run
DELTA DAYS Number of days to skip between each Seq. execution
DELTA TIME Number of hours later each “Delta Days” Seq is to be run
DURATION Number of minutes the sequence operates
CALIBRATE Enable to do a calibration – Disable to do a cal check only