Chapter 1 General Information; Overview; System Configurations - Emerson Rosemount 6888C Instruction Manual

Instruction Manual
00809-0100-4891
1 General information
1.1

Overview

The 6888 is Rosemount's latest combustion flue gas oxygen analyzer. This product is
intended for measuring the flue gases resulting from any combustion process.
This product uses an in situ sensor, i.e., the sensor is placed at the end of the probe, and
the probe extends directly into the flue gas duct or stack at a given length. The sensor is
like a thermocouple, generating its own millivolt signal based on the difference between a
reference gas (ambient or instrument air - always 20.95% O
measured. This manual covers the Rosemount 6888C, which is the hazardous area probe
version.
This probe can be configured as a blind stand-alone transmitter where HART
FOUNDATION Fieldbus
electronics for setup, operation, and diagnostics or with one of several remote electronics
options, as noted below in
of these configurations follow in
There are several different arrangements of probes, electronics, and features that are
explained below and in the wiring diagrams.
1.2

System configurations

1.2.1 Hazardous Area Transmitter probe only
The Rosemount 6888 probe has the electronics in the blue housing that controls the
heater temperature and also amplifies the raw O
4-20 mA signal lines can be run directly to the control room and also power the
transmitter electronics. As with most other Rosemount transmitters measuring pressure,
temperature, and flow, setup is conducted through HART communications via a Field
Communicator or Asset Management Solutions (AMS).
1.2.2 Standard housing Hazardous Area Transmitter probe
with General Purpose Rosemount 6888 Xi Electronics
The Rosemount 6888 Xi Electronics serve as a local operator interface unit, with a back-lit
display and keypad. It is capable of two channels, serving two Rosemount 6888 probes.
The Rosemount 6888 Xi also carries these optional advanced features:
• Fully automatic calibration. Requires Rosemount 6888 Xi O
system
• Loss of flame contact for powering down the heater in the event of a flame-out
condition in a furnace.
• Heaterless operation at process temperatures above 550 °C (1022 °F). This feature will
also permit operation above the heater setpoint of 736 °C (1357 °F). Sensing cell life
will be shortened by operation above 800 °C (1472 °F), however.
Instruction Manual
™
communications can be used as a method of accessing the
System configurations
Electrical installation
General information
) and the flue gases being
2
on page 7. Wiring diagrams for each
on page 25.
millivolt signal to a linear 4-20 mA. The
2
Cal Auto calibration
2
July 2018
®
or
7