Introduction; Overview; Figure 1-1 Digital 7866 Analyzer - Honeywell 7866 Operation And Maintenance Manual

1.1

Overview

The Triple-Range Digital H
•
Range 1: CO
•
Range 2: H
2
•
Range 3: H
2
The analyzer consists of three basic components: the sensing unit (transmitter), the control unit
(receiver)—both shown in Figure 1-1—and a power supply. The sensing unit is located at the sampling
site; the 7866 Digital Controller is arranged for panel mounting in a non-hazardous area.
The sensing unit receives a continuous flow of the binary or multi-component gas mixture, measures the
concentration of the sample gas and transmits an electrical signal to the control unit. The sensing unit is
ruggedly constructed to meet most environmental conditions and is designed to be mounted up to 1,000
feet from the control unit with only a single multi-conductor non-shielded cable connecting the two,
resulting in greater flexibility and lower installation costs.
The control unit receives the output signal from the sensing unit at the sampling site by way of the
interconnecting cable. The control unit is designed for simplified panel-mounting either at the sampling site
if environmental conditions permit, or in a control room. The unit can provide two current output signals to
a remote device for monitoring or recording purposes. The control unit is supplied with one or two alarms.
When an alarm is detected, the specific relay de-energizes creating an open circuit that can activate an
external annunciator or a relay to initiate a shutdown procedure for the process. When power is off the
alarm relay is de-energized.
An indicator model, which provides a continuous readout of the concentration of the gas under analysis, is
also available. The indicator input is connected to the controller's current output. The indicator has no
direct connection to the sensing unit.
9/06 7866 Triple Range Digital H

1. Introduction

and CO Analyzer/Indicator provides three ranges of measurement:
2 2
in Air
2
in CO
2
in Air – See Table 5-3

Figure 1-1 Digital 7866 Analyzer

and CO
2 2
Analyzer/Indicator - Operation and Maintenance
Introduction
1