Instructions

UM-0085-B09 DT80 Range User Manual Page 67
RG
• a, b, c are the constants from the above thermistor equation. If not specified, a coefficient value of zero is
assumed
• units replaces the channel's default units text
Once defined, a thermistor conversion may be applied to any number of resistance channels using the Tn channel
option. For example:
T1=26.5,1.034,8.77e-3"K"
RA1M 3R(T1,"Solvent temp")
See also Temperature – Thermistors (P333).
Intrinsic Functions (Fn)
The DT80 has seven inbuilt and mutually exclusive intrinsic functions that may be applied as channel options. The
intrinsic functions available are
Fn
Description
Text Modifier
F1
1/x
inverse
(Inv)
F2
√x
square root
(Sqrt)
F3
Ln(x)
natural logarithm
(Ln)
F4
Log(x)
base ten logarithm
(Log)
F5
Absolute(x)
absolute value
(Abs)
F6
x * x
square
(Squ)
F7
Gray code conversion (16-bit)
(Gc)
The text modifier is appended to the channel's default units string. If a channel's units string has been explicitly set (using
the
"name~units" channel option) then no modifier is appended.
For example, the channel definition
1V(F2) 2F(F1,"period~sec")
will return data in the form:
1V 455.7 mV (Sqrt)
period 1.7 sec
Combining Scaling Options
The span (Sn), polynomial (Yn), thermistor (Tn) and intrinsic function (Fn) channel options are all mutually exclusive. If
more than one are specified then only the last one will be applied.
Channel variables and Expressions (P70) can be used if multiple scaling operations need to be combined.
Calculations
Channel Variables (nCV)
Channel variables (CVs) are memory locations (registers) for holding and manipulating floating-point data. The DT80 has
1000 channel variables, identified as 1CV to 1000CV.
All channel variables are reset to 0.0 when the DT80 is reset (
HRESET) or cleared (INIT).
Reading Channel Variables
A channel variable behaves in much the same way as any other channel type. Its value may be read (i.e. returned and/or
logged) by including the appropriate nCV channel definition in a schedule. For example, sending
12CV
will immediately return the value of channel variable #12, while
RA10S 1..5CV
will report the values of 1CV through 5CV every 10 seconds.
If a CV is being used for holding an intermediate value then you would normally use the
W channel option to make it a
working channel (which is neither returned nor logged).
Setting Channel Variables
A channel variable's value may be set in several different ways:
• the CV is set to the value of an expression, i.e. nCV=expression