Software Overview
27
SBOU123A – March 2012 – Revised September 2016
Copyright © 2012–2016, Texas Instruments Incorporated
XTR108EVM-USB Evaluation Board and Software Tutorial
If there is an error in the communication between the PC and the USB-DAQ, an error message pops up
as shown in
. In this case, it is recommended to close the EVM software, disconnect the power
and USB cables from the USB-DAQ, and wait a few moments. Next reconnect the power cable, then
reconnect the USB cable. After a few moments, start the XTR108EVM-USB software again.
Figure 19. USB Communication Error
5.1
Block Diagram Tab
The
Block Diagram
tab shown in
is loaded by default during the XTR108EVM-USB software
start-up. This tab primarily serves to display the XTR108 register values in a way that is easy to interpret
because nearly every register hexadecimal value is converted to the real-world setting that the register
represents. Other indicators display the supporting circuitry values for the current configuration. The
remainder of this section provides an in-depth explanation of the function of each group of controls and
indicators in the
Block Diagram
tab. All fields located internal to the XTR108 are controls that can be
manipulated by the user, but it is recommended that only advanced users make changes to the controls in
the
Block Diagram
tab.
For more information about any of the circuitry mentioned in the
section, see the
Theory of Operation
section in the
5.1.1
Input MUX
The Input MUX section of the block diagram shows the connections for the RTD sensor, zero-scale
resistors (R
Z1
through R
Z5
), and common-mode resistor (R
CM
). This section also displays the XTR108 input
multiplexer settings. The multiplexer controls which input channels are connected to the excitation current
sources and the input PGA. The default setting for the multiplexer is to connect the excitation current
source (I
REF2
) and PGA input (V
IN+
) to input channel V/I-0 (RTD channel) and to connect the excitation
current source (I
REF1
) and PGA input (V
IN–
) to input channel V/I-1.
