Evaluation Board User Guide
UG-250
One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
Evaluation Board for 16-Bit, Serial Input, Loop-Powered 4 mA to 20 mA DAC
FEATURES
Full-featured evaluation board for the AD5421
Link options
PC control in conjunction with Analog Devices, Inc.,
system demonstration platform (SDP)
PC software for control
EVALUATION BOARD DESCRIPTION
The EVAL-AD5421 is a full-featured evaluation board, designed
to allow the user to easily evaluate all features of the
AD5421
loop-powered 4 mA to 20 mA DAC. The AD5421 pins are
accessible at on-board connectors for external connection. The
AD5421 evaluation board is controlled via the PC’s USB port in
conjunction with Analog Device’s system demonstration
platform board. The SDP board allows the evaluation board to
be controlled through the USB port of a Windows® XP (SP2 or
later) or Vista-based (32-bit) PC using the AD5421 evaluation
software. The AD5421 serial interface is also accessible at the
testpoint connections on the board.
EQUIPMENT NEEDED
DC power supply unit
SDP for PC control (EVAL-SDP-CB1Z)
Voltmeter or ammeter
DOCUMENTS NEEDED
AD5421 data sheet
DEVICE DESCRIPTION
The AD5421 is an integrated device designed for use in loop-
powered 4 mA to 20 mA smart transmitter applications. The
AD5421, in a single chip, provides a 16-bit DAC and current
amplifier for digital control of the loop current, a voltage
regulator to power the entire transmitter, a voltage reference,
fault alert functions, flexible SPI-compatible serial interface,
gain and offset adjust registers as well as other features and
functions.
Complete specifications for the AD5421 are available in the
AD5421 data sheet available from Analog Devices and should
be consulted in conjunction with this document when using the
evaluation board.
SOFTWARE NEEDED
AD5421 evaluation software
FUNCTIONAL BLOCK DIAGRAM
PC
USB
PORT
EVAL-AD5421SDZ
DIGITAL
ISOLATION
LOOP+
SYSTEM DEMONSTRATION
PLATFORM BOARD
AD5421
LOOP–
09701-001
Figure 1.
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.
Rev. A | Page 1 of 12
UG-250
TABLE OF CONTENTS
Features .............................................................................................. 1
Equipment Needed ........................................................................... 1
Documents Needed .......................................................................... 1
Software Needed ............................................................................... 1
Evaluation Board Description......................................................... 1
Device Description ........................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Evaluation Board Hardware ............................................................ 3
Evaluation Board User Guide
Power Supplies ...............................................................................3
Link Options ..................................................................................3
Evaluation Board Software Quick Start Procedures .....................5
Software Installation .....................................................................5
Software Operation .......................................................................5
Main Window ................................................................................6
Evaluation Board Schematics and Artwork ...................................7
Ordering Information .................................................................... 11
Bill of Materials ........................................................................... 11
REVISION HISTORY
10/11—Rev. 0 to Rev. A
Change to Figure 4 ........................................................................... 7
3/11—Revision 0: Initial Version
Rev. A | Page 2 of 12
Evaluation Board User Guide
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The
AD5421
evaluation board requires one power supply
connection from LOOP− to LOOP+ (J7), a voltage in the
range from 5.5 V to 52 V can be applied if the on-board
MOSFET device (U2) is not enabled. With U2 enabled, the
voltage limit is the breakdown voltage of U2, which in this
case is 240 V. A load resistor can also be connected at J7.
UG-250
Default Link Option Setup
The default link options are listed in Table 1.
Table 1. Link Options
Link No.
LK1
LK2
LK4
LK6
LK7
Alarm_Dir
Rint_Rext
Range0
Range1
Reg_Sel0
Reg_Sel1
Reg_Sel2
Option
Inserted
B
Inserted
Inserted
Inserted
B
B
B
B
A
B
A
LINK OPTIONS
Set the link options on the evaluation board for the required
operating setup before powering on the board. The functions
of the link options are described in Table 2.
Rev. A | Page 3 of 12
UG-250
Table 2. Link Options
Link No.
LK1
Evaluation Board User Guide
Description
This link connects the V
LOOP
input pin to the LOOP+ voltage via a 20:1 resistor divider.
When this link is inserted, the V
LOOP
pin is connected to the resistor divider.
When this link is removed, the V
LOOP
pin is unconnected and can be connected to another voltage (maximum 2.5 V) via TP26.
This link enables/disables the MOSFET device.
Position A disables the MOSFET device.
Position B enables the MOSFET device and the loop supply is connected directly to the REG
IN
pin.
This link enables/disables the
iCoupler®
digital isolators.
When this link is inserted, the isolators are enabled.
When this link is removed, the isolators are disabled.
This link should be inserted when the MOSFET device is enabled (LK2 in Position B).
This link should be removed when the MOSFET device is disabled (LK2 in Position A).
This link completes the loop connection if a load resistor is not connected at Connector J7.
This link should be inserted if a load resistor is not connected at Connector J7.
This link should be removed if a load resistor is connected at Connector J7.
This link selects the alarm current direction.
Position A selects an upscale alarm current (22.8 mA or 24 mA).
Position B selects a downscale alarm current (3.2 mA).
This link selects to use either the internal or external current setting resistor.
Position A selects the internal resistor.
Position B selects the external resistor.
These links select the loop current range.
Range1 Range0 Loop Range
B
B
4 mA to 20 mA
B
A
3.8 mA to 21 mA
A
B
3.2 mA to 24 mA
A
A
3.8 mA to 21 mA
These links select the voltage regulator output voltage.
Reg_Sel2 Reg_Sel1 Reg_Sel0 Regulator Output Voltage
B
B
B
1.8 V
B
B
A
2.5 V
B
A
B
3V
B
A
A
3.3 V
A
B
B
5V
A
B
A
9V
A
A
B
12 V
LK2
LK4
LK6
LK7
Alarm_Dir
Rint_Rext
Range0,
Range1
Reg_Sel2,
Reg_Sel1,
Reg_Sel0
Rev. A | Page 4 of 12
Evaluation Board User Guide
EVALUATION BOARD SOFTWARE QUICK START PROCEDURES
SOFTWARE INSTALLATION
The
AD5421
evaluation kit includes self-installing software on
a CD. The software is compatible with Windows XP (SP2) and
Vista (32-bit). If the setup file does not run automatically, you
can run
setup.exe
from the CD.
Install the evaluation software before connecting the evaluation
board and SDP board to the USB port of the PC to ensure that
the evaluation system is correctly recognized when connected
to the PC.
1.
After installation from the CD is complete, power up the
AD5421 evaluation board as described in the Power
Supplies section.
Connect the SDP board to the AD5421 evaluation board
and then to the USB port of your PC using the supplied
cable. Either connector of the SDP board may be used.
When the evaluation system is detected, proceed through
any dialog boxes that appear. This finishes the installation.
UG-250
SOFTWARE OPERATION
To launch the software, complete the following steps:
1.
From the
Start
menu, select
Analog Devices – AD5421;
then select
AD5421 Evaluation Software.
The main
window of the software displays (see Figure 3).
If the evaluation system is not connected to the USB port
when the software is launched, or if the AD5421 board is
not connected to the SDP board, a connectivity error
displays (see Figure 2). Simply connect the evaluation
board to the USB port of the PC, wait a number of seconds,
click
Rescan,
and follow the instructions.
2.
2.
3.
Figure 2. Connectivity Error Alert
Rev. A | Page 5 of 12
09701-002
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