Campbell Scientific CR9000X Measurement and Control System - Manual (Page 360)

Section 9. Program Control Instructions
Data Statement Examples
This example uses Data to hold the data values and Read to transfer the values
to variables. It uses Restore to read 1, 2, 3, 4 into both X( ) and Y( ) variables.
DATA 1, 2, 3, 4
For I = 1 To 4
READ X( I )
Next I
RESTORE
For I = 1 To 4
READ Y( I )
Next I
Excite (ExSlot, ExChan, ExmV, Delay)
This instruction sets the selected excitation channel’s output to a specific
value. Compliance current for any excitation channel is 50 milliamps. As long
as this current limitation is not exceeded, there will not be any signal
degradation over time.
Channels 1 through 6 are Continuous Analog Output (CAO) channels and will
remain at the excitation voltage set by the instruction unless a subsequent
instruction (Excite or a Bridge instruction) changes the voltage setting for that
channel. Each of the CAO channels has it’s own DAQ and can be
independently set.
Channels 7 through 16 are switched excitation channels. They can be switched
to the excitation voltage for the time specified by the Delay parameter and then
switched off. Only one Switched excitation channel can be active at any given
time.
This instruction must not be placed inside a conditional
statement or in a Slow Sequence Scan. The ExmV variable's
value can be changed conditionally, but it should be remembered
that this task will be done by the processing task sequencer and
can lag behind the measurement task sequencer by the number of
Scan buffers setup by the Scan instruction. NOTE
Parameter
& Data Type Enter EXCITE PARAMETERS
ExSlot
constant The slot that holds the Excitation Module to be used for the measurement.
ExChan
constant The excitation channel to be used. Channels 1thru 6 are Continuous Analog Outputs,
channels 7 thru 16 are Switched Excitation channels
ExmV
Constant, variable,
or expression Excitation voltage to be set in mVolts. Allowable range is –5000 mV to 5000 mV.
Resolution of the setting is 2.4 mV.
Delay
Constant
The Delay parameter is the amount of time, in microseconds, to delay the measurement
task sequencer after the Excite instruction is executed.
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