Campbell Scientific AM25T 25-Channel Solid State Multiplexer - Manual (Page 15)

AM25T Solid State Multiplexer
Mult, Offset: The Mult and Offset parameters are each a constant, variable,
array, or expression by which to scale the results of the measurement. With a
multiplier (mult) of 1 and an offset of 0, the output is in degrees Celsius.
The AM25T instruction must NOT be placed in a conditional
statement when running in pipeline mode. NOTE
6.1.1 Example CRBasic Programs
Both CRBasic example programs are written for CR1000 dataloggers. Other
CRBasic dataloggers are programmed similarly.
6.1.1.1 CR1000 Example Program 1
In this example, 25 type T thermocouples are connected to the AM25T. One
AM25T instruction will measure the AM25T’s PRT and the thermocouples.
Table 6-1 shows the wiring used with the example.
TABLE 6-1. Wiring for CR1000 Example 1
Function AM25T CR1000
+12V Power 12 V 12 V
Power and Shield Ground Gnd Gnd
Clock CLK C5
Reset RES C4
RTD Excitation EX EX1
Common High HI 1H
Common Low LO 1L
Example 1. CR1000 Program Using One Instruction to Measure Both the Reference
Temperature and Thermocouples
‘Declare Public Variables
Public Tref
Public TC (25)
‘Define Data Tables
DataTable (Dat15sec,1,-1)
DataInterval
(0,15,Sec,10)
Sample (1,Tref,IEEE4)
Sample (25,TC(1),IEEE4)
EndTable
DataTable (Dat5min,1,-1)
DataInterval
(0,5,Min,10)
Average (1,Tref,IEEE4,False)
Average (25,TC(1),IEEE4,False)
EndTable
11