Campbell Scientific CR9000X Measurement and Control System - Manual (Page 236)

Section 7. Measurement Instructions
7-12
Parameter Enter BRHALF, BRHALF3W, BRHALF4W PARAMETERS
Dest
Var. 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 Constant The number of repetitions for the measurement.
Range The voltage range for the measurement.
Constant ± 5 Volt Analog Input Module ± 50 Volt Analog Input Module
Alpha
Code Numeric
Code Voltage
Range Alpha
Code Numeric
Code Voltage
Range
mV5000 0 ± 5000 mV V50 6 ± 50 V
mV1000 1 ± 1000 mV V10 7 ± 10 V
mV200 4 ± 200 mV V2 10 ± 2 V
mV50 5 ± 50 mV mV500 11 ± 500 mV
ASlot
Constant
The number of the slot that holds the Analog Input Module to be used for the measurement.
SEChan
Constant
The single-ended channel number on which to make the first measurement. When Reps are used, subsequent
measurements will be made on sequential single-ended channels.
Burst Option
: Enter a negative number to dwell on the specified channel for the # of measurements specified
by the Reps parameter (except for CR9058E). When using burst option, the MesPEx parameter must be set to
the same value as the Reps parameter and a CAO should be used for excitation.
ExSlot
Constant
The slot that holds the Excitation Module for the measurement.
ExChan Enter the excitation channel number to excite the first measurement.
Constant Channels Result
1 - 6 Continuous analog output channels, will remain at the excitation voltage set by the
instruction unless a subsequent instruction changes their voltage
7 - 16 Switched excitation channels, are switched to the excitation voltage for the
measurement and switched off between measurements.
MesPEx
Constant
The number of sensors to excite with the same excitation channel before automatically advancing to the next
excitation channel. To excite all sensors with one excitation channel, MesPEx should equal Reps.
ExmV
Constant
The excitation voltage in millivolts. Allowable range ± 5000 mV. RevEx may be used to excite with both a
positive and negative polarity to cancel offset voltages.
RevEx Option to reverse excitation to cancel offsets. See Section 3.1.1.1 Reversing Excitation or Differential Input.
Constant Value Result
0 Excite only with the excitation voltage entered
1 A second measurement is made with the voltage polarity reversed.
RevDiff Option to reverse inputs to cancel offsets. See Section 3.1.1.1 Reversing Excitation or Differential Input.
Constant Value Result
0 Signal is measured with the high side referenced to the low
1 A second measurement is made after reversing the inputs
SettlingTime
Constant
The time in microseconds to delay between setting up a measurement (switching to the channel, setting the
excitation) and making the measurement (10 microsecond resolution).See Section 3.1.3 Signal Settling Time
Entry
Voltage Range
Delay CR9055
Voltage Range
Delay
0 ± 50 mV 20 µS (default) ± 0.5V 40 µS (default)
0 ± 200 mV 20 µS (default) ± 2 V 40 µS (default)
0 ± 1000 mV 10 µS (default) ± 10 V 30 µS (default)
0 ± 5000 mV 10 µS (default) ± 50 V 30 µS (default)
> 0 all Truncate to closest 10 µS all Truncate to closest 10 µS
Integ
Constant
The integration time in microseconds for each of the channels measured (10 microseconds resolution).
See Section 3.1.1.3 Integration for more information on Integration.
Mult, Offset
Constant, Var.,
Array, or
Expression
A multiplier and offset by which to scale the raw results of the measurement.
The raw result with a multiplier of 1 and an offset of 0 is V
Out
/V
EX
for the BrHalf instruction, and is
V
RS
/V
RF
for the BRHalf3W and BrHalf4W bridge configurations. See text above to convert this over to
sensor resistance value.