EVAL-418-LC

LC Series Basic Evaluation Kit User's Guide customers may("RF") wantproducts Linx radiomay frequency (“RF”) Linx radio frequency be ! Warning: Some products to control machinery or devices remotely, including machinery used to control machinery or devices remotely, including machinery or or devices devices that that can can cause cause death, death, bodily bodily injuries, injuries, and/or and/or property property damage if improperly or inadvertently triggered, particularly damage if improperly or inadvertently triggered, particularly in in industrial industrial settings or other applications implicating life-safety concerns and settings or other applications implicating life-safety concerns.(“Life No Linx Property Safety Situations”). Technologies product is intended for use in any application without redundancies where the safety of life or property is at risk. NO OEM LINX REMOTE CONTROL OR FUNCTION MODULE SHOULD EVER BE USED IN LIFE AND PROPERTY SAFETY The customers No andOEM usersLinx of devices machinery controlled with SITUATIONS. Remoteand Control or Function Module RF products must understand must Safety use all Situations. appropriate Such safety should be modified for Life andand Property procedures incannot connection with the devices, without limitation, modification provide sufficient safetyincluding and will void the product’s using appropriate safety procedures regulatory certification and warranty. to prevent inadvertent triggering by the user of the device and using appropriate security codes to prevent Customers use our controlled (non-Function) Modules, Antenna and of other triggering ofmay the remote machine or device by users Connectors as part of other systems in Life Safety Situations, but remote controllers. only with necessary and industry appropriate redundancies and in with safety standards, without Docompliance not use this or applicable any Linx product to triggerincluding an action directly limitation, ANSI and NFPA standards. It is solely the responsibility from the data line or RSSI lines without a protocol or encoder/ of any Linx customer who uses one or more of these products to decoder to validate the data. Without validation, any signal from incorporate appropriate redundancies and safety standards for the Life another unrelated transmitter the environment received by the and Property Safety Situation in application. module could inadvertently trigger the action. This module does not havenot data builtLinx in. product to trigger an action directly Do usevalidation this or any from the data line or RSSI lines without a protocol or encoder/ All RF products are susceptible to RFvalidation, interference can prevent decoder to validate the data. Without any that signal from another unrelated RF transmitter the environment the module communication. productsinwithout frequencyreceived agility orby hopping could inadvertently trigger the action. implemented are more subject to interference. This module does not have frequency agility built in. All RF products are susceptible to RF interference that can prevent communication. RF products or hopping Do not use any Linx product without over thefrequency limits in agility this data guide. implemented are more subject to interference. This module does have Excessive voltage or extended operation at the maximum voltage could a frequency hopping protocol built in, but the developer should still be cause product failure. Exceeding the reflow temperature profile could aware of the risk of interference. cause product failure which is not immediately evident. Do not use any Linx product over the limits in this data guide. Do not make any or physical or operation electrical at modifications any Linx Excessive voltage extended the maximumtovoltage could product. This will voidExceeding the warranty regulatory and UL certifications cause product failure. theand reflow temperature profile could and may causefailure product failure which is not immediately cause product which is not immediately evident. 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^ 2^ 2^ 3^ 4^ 4^ 5^ 6^ 7^ 8^ 8^ 9^ 10^ 11^ Introduction Ordering Information LC Transmitter Evaluation Board LR Receiver Evaluation Board Theory of Operation Using the Kit Development Using the Prototyping Area Range Testing Using the Boards as a Design Reference About Antennas In Closing Online Resources LR Receiver Evaluation Board Schematic LC Transmitter Evaluation Board Schematic LC Series Basic Evaluation Kit User's Guide Figure 1: LC Series Basic Evaluation Kit Introduction Linx LC Series RF 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 LC Series modules into an end product. The development boards themselves serve several important functions: • Rapid Module Evaluation: The boards allow the performance of the LC Series modules to be evaluated quickly in a user’s environment. • Range Testing: Using the on-board encoders and decoders to generate a simplex 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 custon circuits directly on the evaluation board. All signal lines are available on a header for easy access. The kit includes 2 LC Series transmitters*, 2 LR Series receivers*, 2 extra PCB-mount RP-SMA connectors, 2 evaluation boards, 2 CW Series antennas, 1 CR2032 battery, 2 AAA batteries and full documentation. * One part is soldered to each board. One extra is for use on your first prototype boards. – 1– Revised 3/19/14 Ordering Information LR Receiver Evaluation Board Ordering Information 2 Part Number Description EVAL-***-LC LC Series Basic Evaluation Kit 7 5 *** = 315, 418 (Standard), 433MHz 1 Figure 2: Ordering Information 4 3 LC Transmitter Evaluation Board 6 9 7 8 3 8 1 4 5 6 9 2 Figure 4: LR Receiver Evaluation Board 1. Battery – 3VDC (use 2 AAA style batteries only) 2. Power Switch 3. Prototyping Area 4. Breakout Header 5. LR Series Receiver Module 6. MS Series Decoder 7. Reverse-Polarity SMA Antenna Connector 8. LED - D1 9. Buzzer - D0 Figure 3: LC Transmitter Evaluation Board 1. Battery - 3VDC (use a CR2032-style battery only) 2. Power Switch 3. Continuous ON Switches 4. Momentary Pushbuttons 5. Prototyping Area 6. Breakout Header 7. Reverse-Polarity SMA Antenna Connector 8. LC Series Transmitter Module 9. MS Series Encoder – 2– – 3– Theory of Operation Development Using the Prototyping Area Transmitter Evaluation Board The transmitter board is powered by an on-board 3V CR2032 lithium battery. It has eight SPST pushbutton switches, the state of which is encoded into a data stream using a Linx MS Series encoder. If a switch is closed, the transmitter is enabled while the encoder captures the pushbutton states for encoding and transmission. The encoder powers down the transmitter when the button is released. All of the data lines have been wired out to the header to the right of the prototyping area and can be accessed for use with other switches, contacts or microcontrollers. 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 top and ground at the bottom that can be used to power any circuitry that is added. Receiver Evaluation Board The receiver board is powered by two AAA batteries. The LR Series receiver exhibits a sensitivity of greater than –112dBm, so under optimum line-of-sight conditions, the transmitter / receiver link can operate over distances of up to 3,000 feet (1,000m). The data recovered by the LR Series receiver is decoded by a MS Series decoder, and the data lines are updated to match the state of the data lines (or pushbuttons) on the transmitter board. To demonstrate this, one data line is used to drive a LED while another is used to activate a buzzer. This board also has a prototyping area with all of the receiver and decoder lines brought out to a header. 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. Note: The CR2032-style battery on the transmitter board has very low current capacity with, only about 3mA available for external circuitry. If added circuitry requires a higher current, the battery must be removed and the board powered from an external source. On the transmitter board, the data lines from the encoder have been wired out to a row of plated holes on the right side of the prototyping area. On the receiver board, the data lines from the decoder plus the RSSI, PDN, and DATA lines from the receiver have been wired out. This allows for easy access to connect external circuitry to the modules, the encoder, and the decoder. Data line D0 is connected to the buzzer and D1 is connected to the LED. Using the Kit Using the kit is straightforward. Simply attach the antennas, turn on the power and press buttons on the transmitter board. When S0 is pressed, the buzzer sounds; when S1 is pressed, the LED turns on. When any button (S0–S7) is pressed on the transmitter board, the corresponding decoder output (D0–D7) is active high (VCC) on the prototyping header. – 4– – 5– 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 ransmitter and receiver evaluation boards. To prepare the board for range testing, turn it on by switching the power switch to the ON position. Pressing S0 on the transmitter activates the buzzer on the receiver board, while S1 activates the LED. Switches SW0 and SW1 have been provided to jumper the buttons and continuously transmit. This allows the designer to turn on the transmitter and walk with the receiver. 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. the battery, switch positions, and antenna connection. Next, measure the receiver’s RSSI voltage with the transmitter 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 LC Series data guide or the calculator available on our website for details on microstrip calculations. Since the evaluation boards are intended for use by design engineers, they are not FCC certified. The transmitter 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 LC Series Transmitter 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 – 6– – 7– About Antennas Online Resources 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