Cleveland Motion Controls ULTRA ISC CARTRIDGE TRANSDUCER REV AA - Manual (Page 21)

MAN-70430-0 R EV AA U LTRA S ERIES S TATIONARY S HAFT T RANSDUCER T ECHNICAL M ANUAL
3.3 Summing By “Series Stacking”
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 9 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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