Pulsafeeder Pulsar DLCM - Manual (Page 41)

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Change Constants Procedure
1. Navigate to the Change Constants menu by pressing [CAL]. The {CALIBRATE / PUMP FLOW}
menu is displayed. Press [ENTER] twice. The {FLOW CALIBRATION / 1 POINT} menu is
displayed.
2. Press [UP] until {FLOW CALIBRATION / CHANGE CONSTANTS} is displayed.
FLOW CALIBRATION
CHANGE CONSTANTS
This option is used to set the slope and y-intercept in the equation that describes the linear calibration
curve: y = ax + b. Where 'a' is the slope and 'b' is the y-intercept. The input to this equation (i.e., x) is
given in flow (GPM). The output (i.e., y) represents stroke position in percent (%). The units for the
constants are given on screen. Values can be calculated from two or more flow readings and associated
stroke settings.
3. Press [ENTER] and the display prompts you to enter the slope value:
SLOPE %/GPM
0.3785415569416
You edit the calculated slope value in the displayed units (%/GPM in the example above) value one
position at a time. Press [UP] or [DOWN] to set the digit. Press [ENTER] to move to the next digit.
It is possible for the CHANGE CONSTANTS display of numbers to be larger than the 16 character
screen. If you have a number that overflows the screen in one direction or the other, a greater than (>)
or less than (<) symbol is displayed to indicate this (e.g., <0.3785415569416>). Pressing [ENTER] as
you edit the number string, moves the cursor one position to the right. Pressing [ENTER] on the last
displayed number will shift the display one position to the left. This pattern will continue until the last
digit in the string is reached. Press [ENTER] on the last digit to accept your change.
4. The display prompts you to enter the y-intercept.
y-INTERCEPT
0.00%
Use [UP] and [DOWN] to enter the calculated y-intercept value. The value can be positive or negative
(typically the value will be positive). Press [ENTER]. The {CONFIRM CHANGE? / YES} menu is
displayed. Press [ENTER] to accept your changes. The DLCM will convert the constants to the other
display units automatically.
The display is then returned to its original operating mode.
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Calibration / Tune Flow procedure.
1. In this sub-menu the flow curve can be shifted to 'tune' the flow to one given point. The reason you
might perform this procedure is the process you are currently running is too critical to be shut down to
complete a full calibration. The Tune Flow procedure is a quick fix. Before entering the TUNE sub-
menu, you should measure the actual flow rate at a specific stroke setting. For example, the DLCM is
currently set at 60.0% stroke and it displays a calibrated flow rate of 6.0 GPH. An actual flow
measurement is taken and found to be 5.775 GPH. Leaving the stroke setting at 60%, tune the flow
rate to 5.775 GPH.
Since the {TUNE FLOW} screen displays flow per minute, the flow per hour will have to be
converted:
6.0 GPH / 60 minutes per hour = 0.1 GPM.
5.775 GPH / 60 minutes per hour = 0.09625 GPM
2. Navigate to the Change Constants menu by pressing [CAL]. The {CALIBRATE / PUMP FLOW}
menu is displayed. Press [ENTER] twice. The {FLOW CALIBRATION / 1 POINT} menu is
displayed. Press [UP] until {CALIBRATION / TUNE} is displayed. Press [ENTER] to accept and
continue with the {CALIBRATION / TUNE} menu. The following screen is displayed: