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Definitions continued .
number by the Product Set to determine the number of injections including fractional injections and then
multiplies this result by the additive set. See above Example. Programmable 1-999 gallons.
Flush Alarm Volume
- The minimum amount of product that will not cause a Line Flush Alarm.
Represents the calculated volume of product from the additive injection point in the product line to the end
of the load nozzle. If the flush volume, as programmed, is not counted at the load end, the unit will alarm
"Line Flush Failed", provided the alarm has been programmed Enabled. The alarm indicates an incomplete
flush, leaving contaminated product in the product line. The alarm is used for dye applications where both
clear and dyed products are loaded from the same riser. This alarm will alert terminal personnel that the
product line may not be clear of dye. Program range 0-999 gallons. If a line flush method is not used, the
programmed value is irrelevant.
Line Flush Hardware Input
- Provides the means to accomplish a product line flush by utilizing a
hardware input. Typically implemented by users demanding no co-mingling or contamination of additives
in the product line. The input may be provided from a mechanical preset, electrical preset, terminal
automation system, or any other field device with the capability of signaling the ProPAC-3. Programmable
Enabled or Disabled.
Note:
An actual hardware signal is not necessarily needed. When authorized mode is
enabled and Line Flush Hardware Input is enabled, Line Flush can be initiated by removing the authorize
signal while product flow continues.
Flush Frequency Method
- Provides the means to accomplish a product line flush by utilizing the
product pulse input frequency (Input 1), in order to determine the flush. Programmable either Enabled or
Disabled. If Frequency Flushing is not desired, program Disabled.
Note:
The product pulse input frequency must be 1:1 resolution or higher, as a turbine meter input. A 40:1
product pulse cannot be used! Additionally, it has been found some electronic presets do not provide a 1:1
product frequency that accurately represents the actual load frequency. These presets, due to limitations in
their processing abilities, send product pulses in bursts, thereby, not representing the actual load
frequency. The ProPAC-3 minimizes this problem by allowing the user to average product pulse frequency
over programmable number of product pulses.
Pulse Width Long Average
- This average is used to determine the maximum or full flow rate.
The ProPAC-3 compares this number with the Short Average to determine if the product flow rate has
decreased by the
Flush Start % Decrease
. Programming the Long Average number too large will have no
adverse effect on the performance of the frequency method. There is a flush diagnostic screen in the
ProPAC-3 code. This screen will show the user the Instantaneous value, Short Average, (Max) Long
Average, and the Freq %. The first three values Inst, Aver, Max are all in units of pulses/sec. Instantaneous,
Aver and Long (Max) product pulse frequency are the average over a number of product pulses. Average
numbers should be fairly constant during normal flow. However, if the average numbers are not constant
then increasing the Short and Long Pulse Width Average numbers may be required in order to determine
both an Average (Short) and Maximum (Long) Average product flow frequency. Only used with
Frequency Line Flush.
Pulse Width Short Average
- This average is used to determine the instantaneous flow rate. The
ProPAC-3 compares this number with the Pulse Width Long Average to determine if the product flow rate
has decreased by the
Flush Start % Decrease
. See above. Programming the Short Average number too large
can adversely affect the performance of the frequency method by delaying the detection of product slow
flow. Delaying the detection of slow flow will result in injections during slow flow, hence not allowing
sufficient product to flow after the last injection to clear the product line. It may need to necessary to
decrease
Flush Start % Decrease
number to balance out a larger number in the Pulse Width Short Average.
Only used with Frequency Line Flush.
Summary of Contents for ProPAC-3
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