Datasheet
Table Of Contents
- XTR108EVM-USB Evaluation Board and Software Tutorial
- 1 Overview
- 2 Hardware Overview
- 3 Hardware Setup
- 3.1 Electrostatic Discharge Warning
- 3.2 Connecting the Hardware
- 3.3 Connecting Power and USB to the USB DAQ Platform
- 3.4 Connecting Loop Power Supply to the XTR108EVM-USB Interface Board
- 3.5 Connecting Outputs to a Digital Multimeter (DMM)
- 3.6 USB DAQ Platform Default Jumper Settings
- 3.7 XTR108EVM-USB Interface Board Default Jumper Settings
- 3.8 XTR108EVM-USB Sensor Board Default Jumper Settings
- 4 Software Setup
- 5 Software Overview
- 6 General Operating Tips
- 7 Hardware Documentation
- 8 Appendix
- Important Notices

50*A
PGA
*I
REF
*(RTD
MIN
- R
Z
)
R
VI
I
ZERO
= I
OUT_MIN
-
5*V
REF
8*R
VI
I
ZPGM
=
I
REF
- 5*I
SET
-
N
10
= round[1024 * ]
I
SET
N
11
*I
SET
64
I
REF
- 5*I
SET
N
11
= round[64 * ]
I
SET
N
13
= round[4 * ]
I
ZPGM
I
ZERO
- 35*I
ZPGM
N
12
= round[64 * ]
I
ZPGM
N
13
*I
ZPGM
4
I
ZERO
- 35*I
ZPGM
-
(I
OUT_MAX_MEAS
- I
OUT_MIN_MEAS
)*R
VI
50*A
PGA
*(RTD
MAX
- RTD
MIN
)
I
REF_A
=
(I
ZERO
- I
OUT_MIN_MEAS
)*R
VI
50*A
PGA
*I
REF_A
dR
Z
=
R
Z_A
= RTD
MIN
+ dR
Z
2*B
V
(0.5 + B
V
)*RTD
MAX
- (0.5 - B
V
)*RTD
MIN
- 2*B
V
*R
Z_A
G
LIN_A
=
N
14
= round(16*G
LIN_A
*R
LIN
)
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Appendix
8.2.1.5 I
ZERO
DAC (Zero Offset)
Calculate the required I
ZERO
DAC value.
8.2.1.6 Calculate DAC Codes
The I
REF
and I
ZERO
DACs are controlled by registers 10, 11, 12, and 13 in the XTR108. Use the following
equations to determine the values to be written to these registers. N
10
, N
11
, N
12
, and N
13
are decimal
values that must be converted to hexadecimal before being written.
8.2.2 First Corrections
First, measure the output current at the minimum and maximum temperatures (I
OUT_MIN_MEAS
and
I
OUT_MAX_MEAS
).
8.2.2.1 Linearization Register
Calculate the corrections for the linearization register. N
14
is a decimal value that must be converted to
hexadecimal before being written.
57
SBOU123–March 2012 XTR108EVM-USB Evaluation Board and Software Tutorial
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