Campbell CR5000, Operator'S Manual

Page: 225 / 238

Section 9. Program Control Instructions
9-19
SubScan (SubInterval, Units, SubRatio)
The SubScan instruction is used to control an AM16/32 multiplexer or to
measure some analog inputs at a faster rate than the program scan.
Syntax
SubScan (SubInterval, Units, SubRatio)
Measurements and processing
Next SubScan
Remarks
The SubScan/NextSubScan instructions are placed within the Scan/NextScan
instructions of a program.
SubScans cannot be nested or placed in a SlowSequence. Pulse
Count or SDM measurements cannot be used within a SubScan.
Parameter
& Data Type Enter
SubInterval
Constant The time interval between subscans. Enter 0 for no delay between subscans.
Units The unit of time for the SubInterval.
Constant Alpha Code Numeric Code Units
usec 0 microseconds
msec 1 milliseconds
sec 2 Seconds
SubRatio
Constant The number of times to loop through the subscan each time the scan runs.
The maximum number is 65,535.
Example program:
‘CR5000
'Example Program showing the use of the SubScan instruction to measure
'16 100 ohm Platinum Resistance Thermometers connected to an AM16/32 multiplexer
' used in the 4x16 configuration. The program also measures 6 copper constantan
'thermocouples.
'Wiring:
'CR5000
AM16/32 PRT(4 Wires)
' Control/Common Sensor Terminals
'C1 ------------------------- Reset 1H -----------------Excitation
'C2 ------------------------- Clock 1L ---------------- Excitation Return
'IX1 ------------------------- COM 1H 2H ---------------- Sense wire excitation side
'IXR ------------------------- COM 1L 2L -----------------Sense wire return side
'7H ------------------------- COM 2H
'7L ------------------------- COM2L
NOTE