where “y” is the number of the unused channel selected in Step c and “x”
is the number of the real channel calibrated in Section 10.
Channel No. y’s display should now report a value exactly twice that of
Channel No. x, and with the same precision as was specified for Channel
No. x in Section 10, Step f, above.
f. Change the input to Channel No. x, and the reading of Channel No. y
should change accordingly.
g. To change the
calculation offset constant from “0” (assumed in the above
command) to “1,” type
CLC y = 2.0(CHN x) + 1.0 [CR]
The reading of Channel No. y should now equal twice the reading of Chan-
nel No. x, plus one. Note that the offset (or “b”) term of the CALCULATE
expression is to be entered with the precision desired for the final “calcu-
lated data” reading. In this case, since this term was entered as “1.0,” res-
olution will be to the nearest
tenth of a unit.
Note also that we changed the decimal-point location of the “gain” (or
“m”) coefficient of the CALCULATE expression from “2” to “2.0” in order to
match the resolution of the offset term. It is always recommended that
within a given
CLC statement the gain coefficient and the offset term be
expressed to the same resolution, as indicated by the decimal-point loca-
tion. This will help prevent erroneous off-scale results. It is also recom-
mended that you set up all of your
CLC’s to the same decimal-place
resolution. Mixing
CLC resolutions will tend to slow down the system
scan speed.
h. You may wish at this time to set up and display a second “real-world” data
channel (call it “Channel No. z”), in order to try out some of the CLC func-
tions that operate on two channels—for example,
CLC y = 2.0(CHN x + CHN z) [CR]
or
CLC y = (CHN x)(CHN z)/2.0 + 1.0 [CR]
B - 23
SETUP OF CROSS-CHANNEL CALCULATIONS
“O
NTHE
A
IR
” (B-S
IZED
)
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