EVAL-433MHZ-LT [LINX]
LT Series Basic Evaluation Kit;
| 型号： | EVAL-433MHZ-LT |
| 厂家： | 
Linx Technologies |
| 描述： | LT Series Basic Evaluation Kit |
| 文件： | 总16页 (文件大小：1142K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT Series
Basic Evaluation Kit
User's Guide
Warning: Linx radio frequency ("RF") products may be
!
used to control machinery or devices remotely, including machinery
or devices that can cause death, bodily injuries, and/or property
damage if improperly or inadvertently triggered, particularly in industrial
settings or other applications implicating life-safety concerns. No Linx
Technologies product is intended for use in any application without
redundancies where the safety of life or property is at risk.
The customers and users of devices and machinery controlled with
RF products must understand and must use all appropriate safety
procedures in connection with the devices, including without limitation,
using appropriate safety procedures to prevent inadvertent triggering by
the user of the device and using appropriate security codes to prevent
triggering of the remote controlled machine or device by users of other
remote controllers.
Do not use this or any Linx product to trigger an action directly
from the data line or RSSI lines without a protocol or encoder/
decoder to validate the data. Without validation, any signal from
another unrelated transmitter in the environment received by the
module could inadvertently trigger the action. This module does not
have data validation built in.
All RF products are susceptible to RF interference that can prevent
communication. RF products without frequency agility or hopping
implemented are more subject to interference. This module does not
have frequency agility built in.
Do not use any Linx product over the limits in this data guide.
Excessive voltage or extended operation at the maximum voltage could
cause product failure. Exceeding the reflow temperature profile could
cause product failure which is not immediately evident.
Do not make any physical or electrical modifications to any Linx
product. This will void the warranty and regulatory and UL certifications
and may cause product failure which is not immediately evident.
Table of Contents
1 Introduction
2 Ordering Information
3 LT Series Transceiver Evaluation Board
3 Board Objects
4 Theory of Operation
4 Using the Kit
5 Development Using the Prototyping Area
6 Range Testing
7 Using the Boards as a Design Reference
8 About Antennas
8 In Closing
9 Online Resources
10 Transceiver Evaluation Board Schematics
LT Series Basic Evaluation Kit
User's Guide
Figure 1: LT Series Basic Evaluation Kit
Introduction
Linx LT Series RF transceiver modules offer a simple, efficient and
cost-effective method of adding wireless communication capabilities to any
product. The Basic Evaluation Kit gives a designer all the tools necessary to
correctly and legally incorporate the LT Series modules into an end product.
The evaluation boards themselves serve several important functions:
• Rapid Module Evaluation: The boards allow the performance of the LT
Series modules to be evaluated quickly in a user’s environment.
• Range Testing: Using the on-board transcoders to generate a duplex
transmission, a pair of evaluation boards can be used to evaluate the
range performance of the modules.
• Design Benchmark: The boards provide a known benchmark against
which the performance of a custom design may be judged.
• Application Development: An onboard prototyping area allows for the
development of custom circuits directly on the evaluation board. All
signal lines are available on a header for easy access.
This kit includes 4 LT Series transceivers*†, 2 MT Series transcoders*, 2
extra PCB-mount RP-SMA connectors, 2 evaluation boards, 2 HD or CW
Series antennas and 4 AAA batteries.
* One part is soldered to each board.
†Two extras are for use on your first prototype boards.
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Ordering Information
Ordering Information
Part Number
Description
LT Series Basic Evaluation Kit
EVAL-***-LT
*** = 315, 418 (Standard), 433MHz
Figure 2: Ordering Information
Warning: This product incorporates numerous static-sensitive
components. Always wear an ESD wrist strap and observe proper ESD
handling procedures when working with this device. Failure to observe
this precaution may result in module damage or failure.
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LT Series Transceiver Evaluation Board
2
17
9
5
15
14
1
7
6
16
4
3
8
2
11
13
10
9
5
7
6
1
12
4
3
8
Figure 3: LT Series Transceiver Evaluation Boards
Board Objects
1. Battery – 3VDC
10. LED Button – D2
2. Power Switch
11. Buzzer Button – D3
12. LED – D0
13. Buzzer – D1
14. LED Button – D0
15. Buzzer Button – D1
16. LED – D2
3. Prototyping Area
4. Breakout Header
5. Confirmation LED
6. Routing Switches
7. LT Series Transceiver Module
8. MT Series Transcoder Chip
9. RP-SMA Antenna Connector
17. Buzzer – D3
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Theory of Operation
The two transceiver evaluation boards are identical, but they are populated
slightly differently. The MT Series transcoder is both an encoder and a
decoder, with the input or output nature of each line being determined by
how the board is populated. One board has buttons S0 and S1 populated,
making those lines inputs. On the other board, those lines are connected
to the buzzer and LED, respectively. Conversely, the first board has lines
D2 and D3 connected to the buzzer and LED, while the second board has
buttons S2 and S3 populated. This allows for bidirectional remote control.
To use the kit, simply attach the antennas, turn on the power, and press
one or both of the buttons on a board. When S0 or S2 is pressed, the
buzzer sounds; when S1 or S3 is pressed, the LED turns on.
Both boards have a confirmation LED. When one transcoder sends a
command to the second transcoder, the second transcoder sends a
confirmation back to the first transcoder indicating that the command was
received and the action performed. When the first transcoder receives the
confirmation, it turns on the CONFIRM LED to indicate this. This feature
offers the ability to range test without needing to be in visual or hearing
range of both boards.
The MT Series Transcoder Data Guide goes into the many features of the
transcoders in detail, but this is the only set-up required for operation of
this kit.
Using the Kit
Using the kit is straightforward. Simply attach the antennas, turn on the
power, and press buttons on one of the boards. When S0 or S2 is pressed,
the LED turns on; when S1 or S3 is pressed, the buzzer sounds. When any
button is pressed, the CONFIRM LED lights up to indicate that the other
side got the command.
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Development Using the Prototyping Area
In addition to their evaluation functions, the boards may also be used for
product development. They feature a prototyping area to facilitate the
addition of application-specific circuitry. This area has a connection to VCC
at the bottom and to ground at the top which can be used to power any
added circuitry.
Note: If added circuitry requires a higher current than can be provided
by the batteries, the batteries must be removed and the board powered
from an external source.
The holes are plated and set at 0.1" on center with a 0.04" diameter,
making it easy to add most industry-standard SIP and DIP packages to the
board.
All of the lines from the transceiver have been wired out to a row of plated
holes on the right side of the prototyping area. Four of the data lines from
the transcoder have also been wired out. This allows for easy access to
connect external circuitry to the modules and the transcoder. Three lines
from the transceiver (DATA, T/R_SEL, and PDN) have been routed to
switches. The switches connect the lines to either the transcoder or the
prototyping area. This allows the transceiver to be conveniently switched
between the transcoder and application circuitry during testing.
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Range Testing
Several complex mathematical models exist for determining path loss in
many environments. These models vary as the transmitter and receiver are
moved from indoor operation to outdoor operation. Although these models
can provide an estimation of range performance in the field, the most
reliable method is to simply perform range tests using the transmitter and
receiver in the intended operational environment.
Basic range testing can be performed with the transceiver evaluation
boards. To prepare the board for range testing, turn it on by switching the
power switch to the ON position. Pressing S0 or S2 activates the buzzer on
the receiver board, while S1 or S3 activates the LED. The CONFIRM LED
provides an indication that the signal has traveled round trip, so only one
person is needed to conduct range testing.
As the maximum range of the link in an area is approached, it is not
uncommon for the signal to cut in and out as the transmitter moves. This
is normal and can result from other interfering sources or fluctuating signal
levels due to multipath. Multipath results in cancellation of the transmitted
signal as direct and reflected signals arrive at the receiver at differing times
and phases. The areas in which this occurs are commonly called “nulls”
and simply walking a little further usually restores the signal. If this does not
restore the signal, then the maximum effective range of the link has been
reached.
Since the evaluation boards are intended for use by design engineers, they
are not FCC certified. The transmitter section has been set to approximate
legal limits by resistor R9 so that the range test results will approximate the
results from a well-designed, certified product. For applications where Part
15 limits are not applicable or output levels can be legally raised due to
protocol duty cycle, R9 can be changed according to the Output Power vs.
LADJ Resistance graph in the LT Series Transceiver Module Data Guide.
To achieve maximum range, keep objects such as your hand away from
the antenna and ensure that the antenna on the transmitting board has a
clear and unobstructed line-of-sight path to the receiving board. Range
performance is determined by many interdependent factors. If the range
you are able to achieve is significantly less than specified by Linx for the
products you are testing, then there is likely a problem with either the board
or the ambient RF environment in which the board is operating. First, check
the battery, switch positions, and antenna connection. Next, measure the
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transceiver’s RSSI voltage with the other transceiver turned off to determine
if ambient interference is present. If this fails to resolve the issue, please
contact Linx technical support.
Using the Boards as a Design Reference
The basic evaluation boards included in this kit are very simple, yet they
illustrate some important techniques that should be incorporated into the
board layout. The module’s mounting pads extend slightly past the edge of
the part. This eases hand assembly and allows for better heat conduction
under the part if rework is necessary. A full ground plane fill is placed on the
bottom of the board. This ground plane serves three important purposes:
First, since a quarter-wave antenna is employed, the ground plane is
critical to serve as a counterpoise (please see Application Note AN-00500
“Antennas: Design, Application, and Performance” for details on how a
ground plane affects antenna function).
Second, a ground plane suppresses the transfer of noise between stages
of a product as well as unintentional radiation of noise into free space.
Third, a ground plane allows for the implementation of a microstrip feed
between the module and the antenna. The term microstrip refers to a PCB
trace running over a ground plane that is designed to serve as a 50-ohm
transmission line. See the LT Series data guide or the calculator available
on our website for details on microstrip calculations.
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About Antennas
The choice of antennas is one of the most critical and often overlooked
design considerations. The range, performance, and legality of an RF link
are critically dependent upon the type of antenna employed. Linx offers
a variety of antenna styles that can be considered for a design. Included
with your kit are HD Series (315MHz) or CW Series (418MHz and 433MHz)
connectorized whip antennas that should be connected prior to using the
kit. Despite the fact that the antenna is not centered on the board’s ground
plane, it exhibits a VSWR of <1.7 and suitably demonstrates the module’s
best practical performance.
In Closing
Here at Linx, “Wireless Made Simple” is more than just our motto, it is our
commitment. A commitment to the highest caliber of product, service,
and support. That is why, should you have questions or encounter any
difficulties using the evaluation kit, you’ll be glad to know many resources
are available to assist you. First, check carefully for the obvious, then
visit our website at www.linxtechnologies.com or call +1 541 471 6256
between 8AM and 4PM Pacific Time to speak with an application engineer.
Legal Notice: All Linx kits and modules are designed in keeping with
high engineering standards; however, it is the responsibility of the user to
ensure that the products are operated in a legal and appropriate manner.
The purchaser understands that legal operation may require additional
permits, approvals, or certifications prior to use, depending on the
country of operation.
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Transceiver Evaluation Board Schematics
VCC
S8
VCC
+
B1
BAT-AAA
C1
10uF
GND
GND
Figure 4: Power Supply Section
ANT1
CONREVSMA001
U1
R9
12
1
2
3
4
5
6
RF
1
RF
GND
LADJ
VCC
VCC
S4
750 ohm
VCC
11
10
9
GND
PDNMT
2-5
NC
GND
GND
PDN
SW-SPDT
S5
GND
RSSI
RSSI
A REF
PDN
TRSELMT
8
A REF
T/R SEL
DATA
TRSEL
7
SW-SPDT
S6
ANALOG
TRM-XXX-LT
DATAMT
DATA
SW-SPDT
Figure 5: RF Module Section
S0
TS1
VCC
9
8
7
6
5
4
3
2
1
RSSI
A REF
DATA
TRSEL
PDN
D0
D1
D2
D3
R0
R23
0 ohm
S1
GND
GND
GND
GND
LED
VCC
100K
R1
R21
0 ohm
S2
BUZZER
Test Strip 1
100K
VCC
LED
R2
R18
0 ohm
S3
100K
VCC
R3
R22
BUZZER
100K
0 ohm
Figure 6: Header Section
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U3
A
R19
1
2
3
4
5
6
7
14
13
12
11
10
9
VCC
F
BUZZER
100k
LED
A`
R20
10k
R17
200 ohm
B
F`
E
B`
C2
C
E`
D
BZ1
D0
0.01uF
GND
green
C`
GND
8
GND
D`
BUZZER
CD4069UB HEX INVERTER
R6
GND
100K
R7
GND
GND
GND
GND
100K
R12
R5
U2
VCC
D6
D7
CRT/LRN
ENC_SEL
SER_IO
CONFIRM
TR_PDN
TR_SEL
GND
GND
100k
R13
100K
R4
VCC
GND
D5
D4
GND
100K
R14
100K
D3
D3
GND
GND
LATCH
BAUD_SEL
MODE_IND
D2
100K
PDNMT
TRSELMT
DATAMT
D2
D1
D0
D10
D1
D0
R15
200 ohm
GND
TR_DATA
LICAL-TRC-MT
LED0805
Figure 7: Duplex Range Test Section
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Linx Technologies
159 Ort Lane
Merlin, OR, US 97532
Phone: +1 541 471 6256
Fax: +1 541 471 6251
www.linxtechnologies.com
Disclaimer
Linx Technologies is continually striving to improve the quality and function of its products. For this reason, we
reserve the right to make changes to our products without notice. The information contained in this Data Guide
is believed to be accurate as of the time of publication. Specifications are based on representative lot samples.
Values may vary from lot-to-lot and are not guaranteed. “Typical” parameters can and do vary over lots and
application. Linx Technologies makes no guarantee, warranty, or representation regarding the suitability of any
product for use in any specific application. It is the customer’s responsibility to verify the suitability of the part for
the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY APPLICATION WHERE THE SAFETY
OF LIFE OR PROPERTY IS AT RISK.
Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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©2021 Linx Technologies. All rights reserved.
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