Hardy HI 1769-FC - Manual (Page 44)

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Chapter 4
Refill OP Adjust %/wgt
This is the OP (Output Percentage) Adjust % per unit of wgt. The OP Adjust %/wgt
factor may be estimated by the formula [OPHigh - OPLow]/[HiWeight-LoWeight],
where OPHigh is the observed output percent at gross weight HiWeight, and OPLow is
the output percent when gross weight = LoWeight.
The weight of an ingredient in a hopper can affect the rate of feed. For example, a liquid
at the base of a full hopper is under greater pressure than a liquid at the base of a near
empty hopper. If no adjustment is made, the liquid flows out faster when the hopper is
full than when it is low. When the OP Adjust parameter is ON (i.e., not set to OFF), the
OP Adjust %/wgt value will adjust the OP% rate to compensate for any change in weight
of the ingredient in the hopper. OP Adjust On Learn is used to calculate this value.
Range: -100 to +100 up to six decimal places (Default 0.0)
Parameter 19 Wait Time
Time the controller waits for the material to settle before it calculates the batch total.
Seconds, 0 decimal places. Must be > or = 0
Parameter 20 Low Alarm Shut Down Rate
If the actual flow rate is below the setpoint, the Lo Shutoff alarm can be configured to
signal an alarm condition that can either shut the process down or lower the output to a
set percentage (See Shutoff % Out below). The decimal point is positioned based on the
Rate DP parameter.
NOTE The Lo Shutoff alarm value must be equal to or less than the lowest set point value.
Range: No limits
Parameter 21 High Alarm Shut Down Rate
If the actual flow rate is above the setpoint, the Hi Shutoff alarm can be configured to
signal an alarm condition that can either shut the process down or lower the output to a
set percentage (See Shutoff % Out below). The decimal point is positioned based on the
Rate DP parameter.
Range: No limits
Parameter 22 Alarm Delay
The number of seconds you want the instrument to delay before either a HI shutoff or LO
shutoff alarm after detecting a flow rate that is out of tolerance. This avoids nuisance
shutdowns and gives the system time to clear a problem.
If a product is easily liquefied, set a very short delay to prevent large spills. If a product
tends to plug or bridge set a longer delay.
Range: 0 decimal places. Must be > or = 0.
Parameter 23 Rate Setpoint
The Rate Setpoint is the ingredient target flow rate (Loss in Weight) you want to
maintain for your process. The decimal point is positioned based on the Rate DP
parameter.
Range: Must be > or = 0, < the maximum rate set for rate calibration.
Parameter 24 REC_P_Limit
The proportional term of the PI loop is truncated to this value. Setting this parameter to a
low value makes the system more immune to glitch disturbances, such as someone
nudging the scale, at the expense of making reaction to actual changes slower.
Range: > 0, < 100.0, 1 decimal place.