Hardy HI 1756-nDF User Manual
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Chapter 4
Parameter
Default
Description
Flow Rate
Filter
1
The weight data used in the flow rate calculation can be
derived from one of four filters. The selection is based
on a compromise between the response time required
and the inherent noise within the measured value.
FRF Quality Comment
0
No suppression of flow rate fluctuations
caused by system noise, fast response time to
step change in flow rate
1
Adaptive Flow Rate Filter (default)
Very good at suppressing flow rate
fluctuations caused by system noise, and has a
fast response time to step change in flow rate
2
Long Term Non-Adaptive Filter
Excellent at suppressing flow rate fluctuations
caused by system noise, but has a long
response time to step changes in flow rate
3
Short Term Non-Adaptive Filter
Very Good at suppressing flow rate
fluctuations caused by system noise, and has a
short response time to step changes in flow
rate
REAL Configuration Parameters used in Flow Rate Control
Parameter
Default
Description
Flow Rate
Timebase
4.0
Period of time over which changes in weight are used to
calculate the flow rate. The smallest increment is 100ms.
Unit of time is in seconds.
Overview of Relay Operation
After power up all relay outputs are in the OPEN state, which is assumed to indicate that
the external valves are CLOSED, and will remain in the OPEN state until the unit is
programmed via the output table.
There are two programmable set points per weigh scale channel; each set point is
associated with a relay output. As the 1756 nDF can be a single or dual channel and the
operation of each channel is independent, the relays, target weight and preact values used
on each channel will be referenced as relay RA, target TA, preact PA, relay RB, target
TB, and preact PB.
The HI 1756 nDF implements a change in weight (CIW) algorithm, which requires that
the external system controls if the weight will increase (fill) or decrease (dispense) and
the HI 1756 nDF simply treats the net weight as an absolute value with respect to the zero