Cleveland Motion Controls ULTRA ISC SERIES SLIM CELL TRANSDUCER REV AA - Manual (Page 23)

MAN-70434-0 R EV AA U LTRA ISC S ERIES S LIM C ELL T RANSDUCER
3.3 S UMMING B Y “S ERIES S TACKING ”
The final interface approach to be discussed is to “stack” the two loadcell outputs by wiring the
analog outputs to be “series aiding”. Note that with each loadcell outputs at a maximum of 5VDC,
the sum would be 10 VDC. As should be obvious, loadcell signals greater than 5 VDC each will
likely take most PLC analog inputs over-range.
Figure 8 Stacking the Two Loadcell Outputs
Here is a simple example of software scaling and summing
Command Description
Sample (digitize) LCH and store ; Store digitized LCH.
Sample RCH and store ; Concurrent samples are best.
ADD LCH_OFSET to LCH parameter ; LCH_OFSET is the zero correction constant.
Multiply offset corrected LCH parameter by
LCHGAIN ; This scales the Left Channel for span
ADD RCH_OFSET to Digitized RCH parameter ; RCH_OFSET is the zero constant
Multiply offset corrected RCH param. by RCHGAIN ; This scales the Reft Channel for span.
Add resultant LCH and RCH parameters ; This is the composite tension feedback
Note that sometimes, over-sampling and filtering can be used to generate a robust tension
feedback parameter despite brief disturbances (either mechanical or electrical).
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