CM4 Four-Point Continuous Monitor
CM4 Technical Manual
7-10
Once the relay state is selected, the display reads:
LATCHING RELAYS
The display then reads:
1=LATCHING 0=NON
The cursor is flashing over the current set-up.
5. Press either:
• 1 to select latching, which requires manual reset of
alarms
or
• 0 to select nonlatching, which clears an alarm automatically
once the gas concentration falls below the alarm
threshold.
The display shows the selection:
LATCHING SELECTED
or
NON LATCH’G SELECTED
The CM4 returns automatically to the Output Options menu.
7.4.5 2 mA Fault Operation (3.3.5)
Purpose
Use the 2 mA fault operation function to enable a 2 mA signal on
the current loop that indicates when an instrument fault occurs. The
CM4 differentiates between a power loss and a fault by dropping the
signal to 0 mA after a power loss or CPU failure and 2 mA when an
instrument fault occurs.
When enabled, the fault operation function causes the calibrate current
loop function from the Calibration Mode to include the 2 mA outputs
as part of the CM4’s fault routine. See
the calibrate current loop function.
Instructions
1. Press PROGRAM to exit Monitor Mode.
2. From the 3–SET-UP MENU, choose the subfunction 3–OUTPUT
OPTIONS, then 5–2 mA FAULT OPER.
3 – SET-UP MODE
3 – OUTPUT OPTION
5 – 2 mA FAULT OPER
3. Press ENTER.
4. Press CURSOR ARROW RIGHT to toggle between enabling
and disabling the 2 mA fault signal.
The display reads:
2 mA FAULT=ENABLED
5. Press ENTER to acknowledge the selection.
7.4.6 Enable/Disable Duty Cycle Option (3.3.6)
Purpose
The Duty Cycle option allows you to select a minimum time period
before the next window will advance. With the introduction of XP/XP4
Chemcassette
®
gas calibrations, the Duty Cycle period has been changed
to be as long as the window time for the selected gas calibration family.
The window will not advance regardless of the gas condition. This will slow
the Model CM4’s response, but reduce tape consumption.
The minimum window time (or Duty Cycle) defaults to zero seconds. It
may however be set to a larger number to conserve tape in installations
that have some concentration of gas for long periods of time. The tape
will not advance until the minimum window time has accumulated, even
if the tape is saturated. During periods when the tape is saturated but
prevented from advancing, the CM4 will continue to report the most
珠海司福斯特科技有限公司
www.safedtech.com
