Emerson Rosemount 6888C Quick Start Manual page 30

Quick Start Guide
• HART
• External contact closure.
• Time since the last successful calibration.
If using the O
control loop into manual prior to calibrating. Always inform the operator
prior to calibrating. The Rosemount 6888 Xi Electronics provides an in cal
contact closure for this purpose as well as an initiate cal contact.
The Rosemount 6888 Xi Electronics sequences the calibration gases in turn
into the sensing cell. A 300 second flow time is the factory default for both
gases and also for the purge cycle, which lets the probe signal come back to
the normal flue gas readings. The 4-20 mA signal representing O
held during the calibration cycle or permitted to vary with the bottled gases,
in which case a record of the calibration can be trended at the DCS.
Calibration setup is found under the detailed setup menu.
Probe with integral autocal housing
This probe contains the autocal solenoids within the blue electronics
housing, eliminating the need and cost for an SPS or IMPS solenoid
enclosure. Both calibration gases are permanently piped into two ports on
the probe. It's important to confirm that there are no piping leaks or the
calibration bottles will leak down permanently.
Note
The calibration sequence from the Rosemount
identical to that for the manual/semiautomatic calibration, but note that
with the integral autocal version of this probe it is not possible to conduct a
manual calibration. The factory offers a probe rebuild capability if solenoid
or other failures occur.
CAUTION
Leaks
Calibration gas bottles ARE piped and under pressure at all times, so be
sure to leak-check all fittings, tubing, and connections.
Always use dual-stage pressure regulators.
30
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communications from a Field Communicator or AMS.
measurement for automatic control, always place the O
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October 2019
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6888 Xi Electronics is
Emerson.com/Rosemount
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