Hardy HI 1769-FC - Manual (Page 7)

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Chapter 1
The analog-to-digital converter in the weigh module controller updates 100 times per
second and is capable of 8,388,608 counts of resolution. This allows the instrument to
tolerate large “dead” loads, over sizing of load cells/sensors, and still have sufficient
resolution to provide accurate weight measurement and control.
The module supports both C2 electronic calibration and hard calibration (i.e., traditional
calibration with weights).
Typical Applications
Closed-loop rate control can be used in a variety of material-flow applications, such as
auger, belt, and vibration-based feeders, converting them from volumetric to gravimetric.
The Feeder Controller controls a single-ingredient, single-feeder. It can be operated in
batch, automatic, or manual mode.
Features and Capabilities
C2 ® Calibration
Traditional calibration uses certified test weights. C2 Electronic Calibration allows a
scale to be calibrated without the need for heavy test weights. A C2 weighing system
consists of up to eight load cell sensors, a junction box, interconnect cable, and an
instrument with C2 capabilities (e.g., the HI 1769-FC). Each Hardy Process Solutions
C2-certified load sensor outputs digital information used for calculating the calibration.
When the HI 1769-FC reads the signals from the load sensors, it calibrates the scale
based on the load sensor’s output plus a user-supplied reference point value (from 0 to
any known weight on the scale).
WAVERSAVER ®
When measuring small weight changes, the effects of mechanical vibration and noise
from the feeders and plant environment can introduce substantial interference.
WAVERSAVER factors out vibration, noise, and other interference-related signals from
the load cell so the rate controller can better decipher the actual weight data.
While WAVERSAVER can factor out noise with frequencies as low as 0.25 Hz, five cut-
off frequencies can be selected, with higher frequencies providing a faster response time.
The default factory setting is 1 Hz vibration frequency immunity.
Alarms
Two HI 1769-FC alarms flag deviations from your specified flow rate.
The Rate Tolerance Alarm can alert you concerning flow-rate changes. It can be set to
trigger an alarm bit which, if sent to a PLC, can be used to respond (e.g., sound an alarm)
when the flow rate is above or below the tolerance.
The Rate Exception Control (REC) Alarm is triggered by an out-of-tolerance flow rate
using
a guard band tolerance in conjunction with the Rate Tolerance Alarm. The REC sets
status word bits that can flag a low or high rate. These signals can be used to either send
an alarm or shut down the feeder system. During an REC alarm state that has not resulted
in shutdown, the controller will continue to maintain the flow rate while monitoring the
loss in weight until the rate is within tolerance.
INTEGRATED TECHNICIAN
®
The HI 1769-FC Integrated Technician (IT ® ), which requires an HI 215IT series junction
box, provides built-in system diagnostics that makes it possible to diagnose weighing
system problems. IT allows the reading of individual load sensor voltages and weights
and isolates individual system components for quick and easy troubleshooting.