New HIDS Drum Scales!
Click Here to Learn More!Rate Exception Control (REC) in the HI 2160RC is the filter that selects which data is saved for the refill and rate exception events. The HI 4060, HI 1769-FC, and the HI 1756-FC uses this limit for extreme motor speed changes to accommodate and product density change.
A rate exception event is anytime the rate controller is not able to calculate the loss in weight (LIW). When a REC event occurs, the REC data is used to totalize data, control the LIW, and monitor the LIW until the event has concluded. There is a timer that, if exceeded, can give just an alarm or give an alarm and turn off the motor signal.
The initial setting for a HI 2160RC LIW feeder is 2.0. This says the motor speed control monitor can allow an OP% deviation of 20% and is considered to be within range. A setting of 10.0 is 100% and considered no control. The amount of control and setting level is dependent on your mechanical setup, product density changes and feeding method. This setting is considered a guard band of the LIW rate and establishes acceptable rates. If you are not getting the results you desire, there maybe a mechanical problem or poor rate calibration. Our goal is to produce the best LIW control by reducing the REC setting to its lowest level, creating the tightest control.
This setting is best established by observing the controller during actual run conditions. With a correctly set REC, the displayed "ON" in the lower left corner of the HI 2160 should intermittently change to REC for a brief amount of time. If this doesn't happen periodically once every ten minutes of run time, the REC level is set too high. You should reduce by 0.2 increments until the desired results are observed. Then increase the REC by 0.1.
In the HI 4060, HI 1769FC, and the HI 1756-FC, REC is a percentage of the maximum rate established during the rate calibration. This value can be found under rate calibration results. A recommendation of 6-10% will provide results and still allow deviation for poor product flow control. Also note the error is displayed as RE+ and RE- to indicate if the error is the results of a excessive gain in weight or excessive loss in weight. Set the REC level so an RE+ or RE- display periodically or appears at the slight touching of the scale.
ALL parameter changes for the HI 2160RC should be done in the OFF mode. (The HI 4060 will accept parameter changes in any state.) Enter configuration and then change the REC level. If you are using the HI 2160RC move to the Rate calibration menu and press ENTER at the low or high rate percentage menu selections. This will re-calculate the Rate calibration and post the new K numbers under tuning and control. The REC change will not be properly integrated without the rate calibration step. This is also true with AVERAGES and TIME BASE parameters. These last steps to connect the REC level changes to the rate calibration is not required for the HI4060 Rate controller, the HI 1769-FC, or the HI 1756-FC.
No HI 2160RC parameter changes should be attempted when the instrument is in the ON, run mode. One exception is the Start Refill low setting in auto refill.
What this REC setting accomplishes is that major disturbances will not affect the current run rate and capture the best data for use during refill, REC and start up. Plus the motor control will not chase minor feeder disturbances. You can test this by lightly touching the scale. The controller should drop into REC for two times the time base and averages, and then recover.
