FCT 80
System Software
5-31
80 D/A Conversions
80 ** DAC **
↑
,
↓
,
↵
Enters the menu at function 80.
The digital-to-analog converter (DAC) converts a digital value from
channels 22-27, 32-38, or 42 into a calibrated analog voltage proportional to
any units. There are two such channels (DAC 1, DAC 2) available on the
instrument back panel.
Three output ranges are available for DAC 1 and DAC 2 on the LI-6262
back panel terminal strip; 0-5V, 0-100 mV, and 4 to 20mA.
To convert voltage output V to the value X that is driving it,
X
X
X
R
V X
F
o
o
=
−
+
where R = full scale voltage range (5V or 100mV),
X
F
= the value of X corresponding to full scale voltage (set in FCT 83
or 86), and
X
o
= the value of X corresponding to zero volts (set in FCT 82 or 85).
For current I,
X
X
X
I
X
X
F
o
o
F
=
−
+
−
16
5
4
where X
F
is the value of X corresponding to 20mA and X
o
is the value of X
corresponding to 4mA, the minimum X value expected, because unlike the
voltage outputs, the current output cannot go negative.
