Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 155)

Section 7. Measurement Instructions
7-29
7.9 Peripheral Devices
AM25T (Dest, Reps, Range, AM25TChan, DiffChan, TCType, Tref, ClkPort,
ResPort, VxChan, RevDiff, SettlingTime, Integ, Mult, Offset)
This Instruction controls the AM25T Multiplexer.
Parameter
& Data Type Enter
Dest Variable
or Array
The Variable in which to store the results of the instruction. When Reps are used the
results are stored in an array with the variable name. An array must be dimensioned
to have elements for all the Reps.
Reps The number of channels to measure on the AM25T. Enter 0 to just measure
Temperature.
Range
Constant
Alpha
Code Numeric
Code Voltage
Range
mV5000 0 ± 5000 mV
mV1000 1 ± 1000 mV
mV200 2 ± 200 mV
mV50 3 ± 50 mV
mV20 4 ± 20 mV
AutoRange 5 mV20 - mV5000 Selects range (Sect. 3.1)
mV200C
mV50C
mV20C
20
30
40 ± 200 mV
± 50 mV
± 20 mV
The mV200C, mV50C, and
mV20C ranges pull the channel
into common mode range and
check for open input
Am25tChan
Constant The starting input channel on the multiplexer.
DiffChan
Constant The Differential channel that will be used to make the actual measurements
from the AM25T.
If the channel is entered as a negative number, all reps occur on
that channel.
TCType
Constant The Thermocouple Type Code. Enter -1 to return voltage measurements.
Tref
Variable The variable in which to store/read the AM25T reference temperature.
ClkPort
Constant The Digital Output port number that will be used to clock the AM25T. One
clock port may be used with several AM25Ts.
ResPort
Constant The Digital Output port number that will be used to enable and reset the
AM25T. Each AM25T must have it's own unique Reset line
VxChan
Constant The Excitation Channel number that will be used to provide excitation for
the PRT reference temperature measurement. If 0 is entered for the
excitation channel, the temperature is not measured.
RevDiff Code Value Result (Reversing requires twice as much time to complete)
Constant False 0 Signal is measured with the high side referenced to the low
True ≠0 A second measurement is made after reversing the inputs to
cancel offsets