Metek 920, Operator'S Manual With Essential Health And Safety Requirements

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4-64 | Model 920 Multi-Gas Analyzer
Remote Start of Auto-Calibration
The Auto-Calibration can also be initiated by a remote, dry (potential free)
contact closure connected to
Pins 10 and 11 on J108 of the Termination
board (Figure 4-8). The contact must remain closed for at least 2 seconds
(up to 5 seconds). A remote start of the Auto-Calibration does not reset
the
ACal Timer to its initial value. The start of the next Auto-Calibration
will be timed from the continuing countdown of the original ACal Timer
setting.
Example:
The ACal Timer is set at 2 hours, the time remaining until the next timed
Auto-Calibration is 30 minutes, and the Auto-Calibration sequence is
started by a contact closure. This will reset the
ACal Timer and the time
remaining until the next timed Auto-Calibration remains 30 minutes. If a
timed Auto-Calibration is in progress, the remote-contact closure will be
ignored.
If the remote start is requested by a Distributed Control System
(DCS) which is also calculating calibration drift values, you must en-
sure that the DCS is the only source of Auto-Calibration requests. The
ACal timer must be set to ‘ 0 ’ for this application. For more informa-
tion, see “Timed Start of Auto-Calibration” in this section.

NOTE