Hardy HI 1756-FC - Manual (Page 49)

If the output is properly wired back to the motor speed controller, verify that the PLC
analog card parameters for that analog out are set correctly and that the HI 1756 FC
analog signal is programmed for the corrected controller terminals.
NOTE Hardy Instruments Inc. does not provide motor speed control converters or analog out
PLC modules. Consult the motor speed controller manufacturer’s manual for
troubleshooting and settings.
REC +/- settings
1. The rate exception control indicates whether the controller is running within the
requested range. If a status bit is out-of-range, the REC status bit is displayed to
indicate the direction. While this may indicate that the rate is too small for the
scale’s accuracy or resolution, the reading can be used to determine the effect of
parameter and mechanical adjustments on improving the material flow control.
2. During auto rate calibration the PI settings are adjusted to optimize the flow rate
for your feeder settings and material. The speed of oscillation can be used to
view the effect of correction or adjustments to the PI settings.
 P = 0-100% correction factor. P determines the amount of action or reaction
that is made in response to an out-of-range rate indication
 I = the speed of that action/reaction. This value normally requires only a
small adjustment. (0.2 increments) If the rate is always high, reduce the I. If
it is always low, increase I.
The feeder fails to stop in HOLD, STOP or IDLE
Determine whether the motor speed control OP% analog card module reacts properly and
goes to the low setting.
1. Verify with a multimeter.
2. Follow the manufacturer’s troubleshooting guide(s) to determine the
malfunction.
3. Verify that the Analog out is returning to the low parameter setting as set in the
PLC menu for that analog out channel.
NOTE Send a Stop or Hold signal when a stop condition occurs. Do not rely on the analog
signal to stop the feeder.
System and Load Cell Tests
Overview of Typical Load Cell System
The typical load cell system consists of one or more load cells/points and an HI 1756 FC
Rate Controller. If you have more than one load point, an optional summing junction box
can read data for individual load cells.
Load Cell/Sensor/Point - is a strain gauge-based force transducer that generates an
electrical signal proportional to the load applied to the scale. Tension or compression type
load cells/points can be used to measure pressure, load, or torque.
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Chapter 6 ●
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