Hardy HI 1756-nDF - Manual (Page 42)

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Chapter 4
Parameter 32 p gain
Gain value used to scale the proportional error term.
The proportional error term is generated by scaling the difference between the
programmed target weight and the final weight value measured on the scale at the end of
the last fill/dispense cycle. The larger the p_gain value, the faster the loop will
compensate for a constant step change in the process but the larger the error will be for
random fluctuations in the process.
The p_gain value can be programmed to a maximum value of 1.0, which represent 100%
of the measured error or to 0.0 which disables the proportional compensation in the P+I
calculation.
Parameter 33 i gain
Gain value used to scale the integral error term.
The integral error term measures the difference between the programmed target weight
and the final weight value measured on the scale at the end of the last cycle, but instead
of making a single change to the auto_preact value this error is integrated over multiple
fill/dispense cycles. In cases where a step change in the process are encountered the
integral term will eventually reach the desired weight value and the target error will
diminish to zero. In this situation as the target error value tends towards zero the impact
on the preact value is also reduced so the response of the system is directly proportional
to the i_gain value used.
The i_gain value can be programmed to a maximum value of 1.0, which represent 100%
of the measured error or to 0.0 which disables the integral compensation in the P+I
calculation.
Parameter 34 frc tolerance
Percentage changes in the flow rate changes below this value are ignored and no changes
to the auto_preact value are made.
Parameter 35 fast adjust
If the channel is being used in a simultaneous or sequential feed mode, then this sets the
percentage the fast relay is adjusted by if the auto preact algorithm exceeds the target
weight.
REAL Status Values
Parameter
Name Parameter
Number Description
Historical Flow
Rate 55.0 The averaged flow rate value. The period over which this
value is calculated is set by the capture averages
parameter.
Preact A 56.0 The current preact value for relay A
Preact B 57.0 The current preact value for relay B
Last Flow Rate 58.0 The flow rate from the last fill/dispense cycle
Last Fill
Weight 59.0
The measured weight at the end of the last fill/dispense
cycle