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Displays And Controls - Honeywell CM4 Technical Handbook

Four-point continuous monitor
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CM4 Four-Point Continuous Monitor
Detection is accomplished by routing the sample from each of its four
points through a high-temperature device (pyrolyzer). For example, at
high temperature, NF
is converted to Hydrogen Fluoride (HF) which
can be detected with a standard Mineral Acids Chemcassette
correlation algorithm between HF and NF
so the instrument's display and printouts read directly in ppm of NF

1.4 Displays and Controls

Figure 1-2
The displays and controls clustered on the front panel of the CM4
Status and Alarm LEDs
1.4.1 Display
The CM4 uses a 1-line, 20-character display. The CM4 display includes
information about concentration and instrument faults and provides
menus for CM4 programming. For more information on the display
panel, see
1.4.2 Status and Alarm LEDs
Status LEDs light green when the CM4 is monitoring the point. There
is one LED for each point.
Light green - normal operation
Flash green - point lock-on or display lock-on at that point
Light yellow - instrument fault on that point
Turn black - not monitoring that point
Status LEDs also turn yellow or flash to indicate an instrument fault.
Alarm LEDs signal gas level alarms for each point. Alarm LEDs:
CM4 Technical Manual
tape. The
is programmed into the CM4-P,
Power LED
Flow Control
Light for Level 1 alarm concentration
Flash for Level 2 alarm concentration
1.4.3 Keypad
Use the keypad to:
Program the CM4
Select specific points to monitor
Print and display programming parameters
1.4.4 Power LED
The power LED at the bottom right of the panel indicates the CM4
is powered up. A blinking yellow power LED indicates the keypad is
locked, requiring a passcode for any CM4 operation.
1.4.5 Flow Control
Four metering valves, one for each point, control the sample flow
through the Chemcassette
1.5 Electrical Connections
All electrical connections are made at the rear of the CM4. User
installed wiring connects to a removable relay panel at the top of the
instrument, allowing the chassis to be removed without disturbing
1.5.1 I/O Panel
The I/O (Input/Output) panel contains connections to 14 form C relays
to activate external devices:
A watch dog relay (RY12) which indicates power loss or a
CPU failure
Eight gas alarm relays which indicate Level 1 and Level 2
Two general gas alarm relays which indicate Level 1 and Level
detection system.


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