How The Instrument Operates 3.1 - Partlow MRC 7800 Installation, Wiring, Operation Manual

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How The Instrument Operates 3.1

3.1.1 OFF MODE
In the Off mode, the instrument alarm and preset function(s) is/are turned off, pulsed output(s)
are inactive and process retransmission signal(s) remain(s) active. The chart rotation can be
selected in the Program mode to stop or continue to rotate when the instrument is in the Off
mode. The pen remains active. The totalization function is inactive, but datalogging functions
continue.
The Off mode is entered by pressing and releasing the SCROLL key until the display reads
oFF, then pressing the DOWN key. If the instrument was displaying process value, the
display will read oFF, then the current process variable at two second intervals. If the
instrument was displaying total, the display will read oFF, then the total at two second
intervals. Entering the Off mode of a dual pen instrument will cause both pens to enter the Off
mode. The second pen display will be blank as the upper display reads oFF and displays the
value for the second pen at the same time as the upper display.
To exit the Off mode, depress the SCROLL key to proceed to any other mode, pressing the
DOWN key to enter that mode.
3.1.2 OPERATE MODE
In the Operate mode, the instrument alarm function(s), the preset function(s), the pulsed
output(s) and the process retransmission signal(s) are actively responding to the process
variable as selected in the Program, Alarm Set and Preset modes and the chart will be
rotating at the rate selected. The totalization function is active, as is the datalogging function.
3.1.2.1 TOTALIZATION
Totalization can be implemented on instruments provided with the totalization feature.
Totalization can be programmed on or off for each pen.
To initiate totalization, depress the SCROLL key until oPEr is displayed, then depress the
DOWN key.
To view the total, depress the DISPLAY SELECT key once with the PV value displayed. The
TOT light should be lit and the total for Pen 1 in the upper display and the total for Pen 2 in the
lower display.
Instruments with Totalization and second display will have the total displayed in the lower
display whenever the upper display is set to PV.
On two pen units only, a Combined Total is available. When activated in the Program mode
an additional step is added to the display choice sequence provided by the Display Select
Key.
If the totals are displayed and the DISPLAY SELECT key is depressed, the Combined Flow
Rate will appear in the top display with a C in the leftmost digit and the Combined Total will
appear in the bottom display. The PV and TOT indicators will be lit, respectively.
Note: When Combined Total is being used, it is required that the decimal position,
dPoS, and totalizer decimal position, tdP, in the Program mode, for both pens are the
same. When the totalizer for Pen 1 is reset, the combined total is also reset.
Upon sensor break, the Combined Total will increment at a indeterminate rate.