Emerson Rosemount 6888C, Instruction Manual

Page: 8 / 88

• Plugged diffuser diagnostic operates by measuring the return-to-process rate after
calibration gas has been stopped. This feature also includes auto gas switching when
the reading settles out versus waiting for configured gas flow time to expire.
• Stoichiometer - If a furnace goes into a reducing condition (0% O
2
), this feature will
determine how far.
• Programmable reference - Permits more accurate readings at near-ambient O
2
levels
(20.95% O
2
).
• A cal check capability. New calibration values are not automatically stored after a
calibration. An accept/reject calibration feature can be enabled or disabled so that the
technician or operator can decide to accept or reject a potentially large change in
calibration values.
• Tolerance check that will alarm if the wrong test gases are being used or if a bottle runs
out in the middle of a calibration. Care must be taken to ensure gas 1 and gas 2
calibration gases are properly configured if the tolerance check feature is enabled.
1.2.3 Hazardous Area Rosemount 6888C probe with General
Purpose Rosemount Xi Electronics with flame safety
interlock
A flame safety interlock by Emerson ™ is available for heater power disconnect whenever
there is a loss of the process flame or a heater runaway condition (heater over-
temperature) in the O
2
probe. This input is internally powered by the Rosemount 6888 Xi
and is actuated via a dry contact input from the user's flame scanner. A closed contact
indicates a flame is present. An open contact indicates a loss of flame. This feature is also
available with the Integral autocal housing.
1.2.4 Hazardous Area Rosemount 6888C probe with Integral
Autocal General Purpose Rosemount 6888 Xi Electronics
This probe contains gas-switching solenoids so that the Rosemount 6888 Xi Electronics
can control the introduction of calibration gases. Calibrations can be intiated via a
calibration recommended diagnostic, time since last calibration, manually via external dry
contact, HART communications, or from the Rosemount 6888 Xi local operator interface
keypad. The integral autocal feature can only be implemented when the probe is used
with a Rosemount 6888 Xi.
1.2.5 Hazardous Area Rosemount 6888C probe with Integral
Autocal and Foundation Fieldbus (FF) communications
This probe contains gas-switching solenoids that can control the introduction of
calibration gases for calibration. Calibrations can be initiated automatically via a
calibration recommended diagnostic, time since last calibration, or manually via optional
Xi keypad, FF communications via the Field Communicator, or AMS console. Unlike the
HART transmitter electronics, the FF version can execute automatic calibrations either
with or without the optional Rosemount 6888 Xi Electronics. Likewise, advanced features
can be implemented either with or without the optional Xi.
General information Instruction Manual
July 2018 00809-0100-4891
8 6888C