_________________________________________________________ DANLOAD
The units of measure displayed are a function of the meter calibration K-factor. The meter
K-factor is given as the number of pulses input into the DANLOAD system per unit of measure
pumped. This factor is usually marked on the meter by the factory (typically 23.5 +/- .5 for a
4" system). The meter K-factor is entered as "XX.XXXX". The DANLOAD system permits
meter K-factors from 1.0 to 99.9999. Meter factors of less than 1.0 are not permitted because
there would not be sufficient pulse generation per unit of measure for the system to control valve
closure properly. A meter K-factor of 10.0 or greater is recommended.
Valve control is achieved by stepping the valve, open or closed, until the desired flow rate is
attained. The valve position is then adjusted every one second throughout the load, if necessary,
to maintain the desired flow rate of + or - 5%. If the flow rate cannot be achieved, the
DANLOAD steps down to the programmed medium flow rate, if it being used. If this rate cannot
be achieved, the DANLOAD "locks-in" at the flow rate which is currently being pumped (see
also Sections 5.0 and 11.0 on meter calibration). This feature results in true digital valve control
and in the ability to maintain a stable flow rate even during varying pressure/demand situations.
Additionally the more stable the flow, the better the results of meter repeatability.
Operator selectable minimum flow rate and time-out values are used to continually check the
current flow rate against the set values. If the flow rate remains below the minimum value for
a period greater than the time-out value, the alarm relay is enabled and an alarm condition is
declared.
The operator also selects the time out period that is permitted after the product is authorized
before pulses must be sensed. This limits the volume of product that would be permitted to flow
in the event the pulser should fail. This value is also used to check for the loss of pulses during
a load. A "no flow" condition causes the alarm relay to be enabled and an alarm condition is
declared.
During periods when product flow is not authorized, the DANLOAD system monitors the pulser
input, looking for unauthorized product flow. The operator can program a value for the
allowable unauthorized flow between loads. If the unauthorized flow value is exceeded, the
system enables an alarm relay and declares an alarm condition.
While normal loading is in progress, the user can stop the flow of product by pressing the "C",
STOP LOAD, key. The DANLOAD system then ramps the DANFLO valve back into low flow
and then stops the flow by fully closing the valve. To start flow again, the user must enter a new
preset value. If the volume to load is the remainder of the original preset, the quantity may be
obtained from the top numeric display.
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SECTION 1
6