CM4 Four-Point Continuous Monitor
CM4 Technical Manual
10-5
10.3 Sample Line Integrity Option
The Sample Line Integrity Option is enabled as a factory setting. The
instrument must have the appropriate and correct sensing hardware
properly installed. If the hardware is defective or not present, the
Model CM4 will display zero after the characterization has been
completed.
The mode is enabled or disabled from the Service Mode menu. This
menu is displayed only if the option has been factory-enabled.
Instructions
After installation, the feature is accessed through the Service function.
To access the menu:
1. Press PROGRAM to exit Monitor Mode.
2. From the 4 – SERVICE MODE, choose the subfunction 8 –
PUMP LIMITS then choose 3 – LIT (Line Integrity Test)
4 – SERVICE MODE
8 – PUMP LIMITS
3 – LIT
The display reads:
SELECT 1 ENABLE
SELECT 0 DISABLE
This will cause one of the following (example) serial printer
messages:
10/24/00 17:44 CM4 - 123 - 0002
Line Integrity Test Disabled
or
10/24/00 17:44 CM4 - 123 - 0002
Line Integrity Test Enabled
Selecting ENABLE 1=Y enables the line check diagnostic. Once
enabled, the Model CM4 establishes a baseline value for each sample
line. It does this (with the pump off) by waiting 20 seconds and then
taking 10 zero-readings on each of the four sample points. When
complete, the Model CM4 switches the pump on, waits 10 seconds,
and then takes an additional 10 zero-readings on each point. The
difference between these values for each point is the baseline for
each sample line.
The baseline variables (delta pressure and enable) are maintained
in BBRAM (battery-backed RAM) and not in EEPROM fields. This
means that they will be erased by Function 4.4 and also by installing
new software.
While the baseline and pump profile measurements are being
established, the Model CM4’s display shows:
CHARACTERIZING
or
NOT AVAILABLE
If all the transducers read 0, the display will then indicate:
LIT SETUP DONE
The next display shows the delta counts for all four points as shown
in this example:
108 77 79 91
The LIT (Line Integrity Test) maintenance fault has been assigned to
Fault code 41. It is a maintenance fault with no yellow lights and no
beeping (similar to the way Fault 40, Pyrolyzer Check Valve Leak is
reported).
The Sample Line Integrity Check will periodically execute at or around
the prescribed user-specified TWA times.
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