EPC C1G2 COMPLIANT BATTERYLESS QUAD 45KGF COMPRESSION LOAD ...

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ATLAS-Q100L

Datasheet

EPC C1G2 COMPLIANT BATTERYLESS QUAD 45KGF COMPRESSION LOAD METERCheck for samples: ATLAS-Q100L

FEATURES

• 860MHz-960MHz operation

• EPC Class-1 Generation-2 compliant

• ISO 18000-6 Type C compliant

• 96-bit EPC & 32-bit TID

• Compression load metering

• 4 channels

• Compression load range: 0kgf to 45kgf

• Compression load resolution: 52gf

• Compression load accuracy: ± 0.5kgf

DESCRIPTIONATLAS-Q100L is an EPC Class-1 Generation-2(C1G2) RFID tag based on Farsens’ batterylesssensor technology. Built in a compact PCB format, thetag includes four independent compression load cellseach one supporting up to 45kgf of load.

These RFID sensor tags are compatible withcommercial UHF RFID readers (EPC C1G2). Witha 2W ERP setup the battery-less load sensor cancommunicate to over one meter and a half - 5 feet.

The ATLAS-Q100L is available in a variety ofantenna design and sizes, depending on the specificapplication. It can be encapsulated in an IP67 or IP68casing for usage in harsh environments.

BLOCK DIAGRAMThe ATLAS-Q100L tag consists of an ANDY100 ICfor energy harvesting and wireless communication,a start-up circuitry based on a voltage monitor,a microcontroler with integrated ADC (10 bits)and signal conditioning circuitry for readingfour independent Wheatstone bridges. AFX19-0-1-0001-0100-L compression load cell isincluded in each channel.

D1

ANDY100D

RF+

RF-

CAL[2]

EERST

CS

SC

K

MIS

O

MO

SI

CAL[1]

CAL[0]

VD

D

2V

5

1V

8

1V

2

GN

D

VIO

µController

CS

MOSI

MISO

VDD

GND

VREF

GPIOS

Signal Conditioning

REF

CTRL

SCK

VoltageMonitor

PG

VDD

GND

VDDTAG VDDSENS

GNDSENS

GNDTAG

C1

GND

VDD

ADC SOUT

CH1

CH2

CH3

CH4

FX1901

FX1901

FX1901

FX1901

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ATLAS-Q100L

Datasheet - DS-ATLAS-Q100L-V02 - OCTOBER 2015 WWW.FARSENS.COM

FX1901

Signal Conditioning

D1

ANDY100D

RF+

RF-

VIOVDD

CAL[0]

GND

EERST CSSCKMOSIMISO

CAL[1]

CAL[2]

µController

CS

MO

SI

MIS

O

A0 SO

SC

K

VDDTAG VDDSENS

GNDSENS

GNDTAG

C1

VoltageMonitor

PG

1.8V 2.4V

SPI

Flash RAM

CPU

ADC

GPIOs

RF

Fro

nten

d

EPC C1G2 / ISO18000-6Cprocessor

SPI masterEEPROM

Power Supply Management

Clock oscillator

VDD

GND

VDD

GND

VDD

GND

Amplifier

IO1

IO2

EN

G+ G-

RG

VREF

IO3

VR REF

S1+

S1-

VN1

S2+

S2-

VN2

VP2

S3+

S3-

VN3

VP3

S4+

S4-

VN4

VP4

Multiplexer

VP1

CHCH

FX1901

FX1901

FX1901

The ANDY100 IC includes a RF frontend for UHF RFID power harvesting and communication, a power supplymodule to generate the required voltage levels, a EPC C1G2/ISO18000-6C digital processor including a trimmedclock oscillator, a non volatile memory and a SPI master module. The SPI master module can be controlled viaEPC C1G2 standard memory access commands.

In order to isolate the supply of the RFID tag from the supply of the rest of the system, the diode D1 is included.The capacitor C1 acts as an energy storage unit to support current peaks of the system during active operation,such as initialization and measurement.

A voltage monitor is included to connect the sensor system only after the energy storage capacitor has beencharged. The voltage monitor connects the sensor system when the voltage in the capacitor is over 2.4V anddisconnects the sensor system when the voltage falls below 1.8V. This architecture avoids oscillation of thesystem during initialization.

The operation of measuring low voltage values is controlled with a micro-controller. Besides the CPU, the flashmemory and the RAM memory the micro-controller includes a SPI module, GPIOs, a 1.5V voltage reference anda 10 bit SAR ADC.

Finally, the signal conditioning is composed of an instrumentation amplifier and a multiplexer. The amplifier canbe configured to have any gain between 1 and 1000 by setting the appropriate value of a resistor. The multiplexeris controlled by gpios and routes the sensor supply voltage and the differential input of the amplifier to one of thefour channels. The signal conditioning circuitry can be enabled/disabled with a nmos switch in order to reducepower consumption when no measurements are being made.

Upon receiving a SPI directed read request from the UHF RFID reader, the ANDY100 generates SPI signalingtowards the micro-controller. Given that the RFID communication protocol specifies timing restrictions for answer,the micro-controller returns the measurement value stored in a buffer and triggers a new measurement. Thus,the answer of the tag to the reader includes the value of the previous measurement.

In order to execute a new measurement, the micro-controller enables the signal conditioning, waits for thestabilization of the amplifier and sets the multiplexer to route the signals towards the first channel. After waitingthe sensor stabilization time, an ADC measurement is taken using the 1.5V reference, and the multiplexer is

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ATLAS-Q100L

Datasheet - DS-ATLAS-Q100L-V02 - OCTOBER 2015

configured to route the second channel. This process is repeated to read the four channels. Afterwards, thesignal conditioning is disabled again to minimize power consumption.


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ATLAS-Q100L


CHARACTERISTICS

SYMBOL PARAMETER MIN TYP MAX UNIT

RFID

RFSENS RF sensitivity fully passive -4 -2 0 dBm

OPERATING CONDITIONS

TOP_TOP Operating temperature range -30 85 ◦C

LOAD METERING

CLrange Compression Load range 0 45 kgf

CLacc Compression Load accuracy -0.5 0.5 kgf

CLres Compression Load resolution 52 gf



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ATLAS-Q100L


OPERATION

EPC reading

In order to read the EPC of the tag, commercial EPC C1G2 readers can be used. However, some considerationshave to be taken into account.

As the tag has a significant supply capacitor connected to VDD, the power-up of the system will be slow. It canlast several seconds. In order to speed up the charge process, the reader shall be configured to send poweras continuously as possible. Refer to the application note External capacitor on VDD of ANDY100 for detailedinstructions on how to set up the reader for best performance.

Once the supply capacitor is charged, the tag will respond with its EPC. From this point on, memory accesscommands can be used to control additional functionalities via the SPI bridge.

Read measurements

The ADC reading of the compression load cells connected to the ATLAS-Q100L can be read using standardEPC read commands. It is important to take into account that the values returned to such a request contains thereadings of the previous measurement. As the measurement process takes longer than the communication, uponreceiving a voltage reading request the tag answers with the value of the previous measurements and triggers anew one. In order to get an up to date measurement, it is mandatory to perform at least two readings.

Read measurements Operation: ReadMemory bank: User MemoryWord Pointer: 0x03Word Count: 6

The answer from the tag to such a request will contain 12 bytes of data. The EPC word size is 16bits and theSPI word size is 8bits. The answer received from the SPI interface is right aligned in the EPC words. Assumingthat the reader returns the received data in the buffer of bytes rawdata, the content of the answer is defined asfollows:

Byte 0

0x00 FW_VER 0x00 CH1[9:2] 0x00CH1[1:0]CH2[9:4]

0x00CH2[3:0]CH3[9:6]

Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7rawdata

content 0x00CH3[5:0]CH4[9:8]

Byte 8 Byte 9

0x00 CH4[7:0]

Byte 10 Byte 11

• FW_VER: firmware version included in the micro-controller.

• CH1[9:0]: 10 length ADC reading from channel 1.





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ATLAS-Q100L


The conversion from the ADC readings to the actual compression load values has to be done by software in thereader side. In order to make the conversion, the calibration constants K 11, K 12, K 21, K 22, K 31, K 32, K 41,and K 42 have to be known. The conversion to compression load value can be done as shown in the followingsample code:

short ADCvalCH1, ADCvalCH2, ADCvalCH3, ADCvalCH4;

float CLCH1, CLCH2, CLCH3, CLCH4;

// Get ADC measurement

ADCvalCH1 = (UInt16)((rawdata[3] << 2) | rawdata[5] >> 6) & 0x3FF;



ADCvalCH4 = (UInt16)((rawdata[9] << 8) | rawdata[11]) & 0x3FF;

// Calculate measured compression loads

CLCH1 = K11 + K12*ADCvalCH1;




Read calibration parameters

The calibration parameters are stored in non volatile memory. Each channel requires two parameters to convertthe ADC reading into an actual measurement. Each parameter consists of a 32 bit floating point value. Theseparameters can be read through the EPC C1G2 interface reading the following addresses of the user bank. It isimportant to take into account that the values returned to such a request contains the readings of the previousoperation. In order to read a calibration parameter, it is mandatory to perform two readings and use the secondanswer.

Read K11 Operation: ReadMemory bank: User MemoryWord Pointer: 0x05Word Count: 5

The content of the answer to such query is defined as follows:

Byte 0

0x00 FW_VER 0x00 K11_XL 0x00 K11_L 0x00 K11_M


content 0x00 K11_S

Byte 8 Byte 9



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ATLAS-Q100L



• K11 (XL:L:M:S): channel 1, calibration word 1 (float32).



Byte 0



content 0x00 K12_S

Byte 8 Byte 9



Read K21 Operation: ReadMemory bank: User MemoryWord Pointer: 0x0DWord Count: 5


Byte 0



content 0x00 K21_S

Byte 8 Byte 9




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ATLAS-Q100L




Byte 0



content 0x00 K22_S

Byte 8 Byte 9





Byte 0



content 0x00 K31_S

Byte 8 Byte 9






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ATLAS-Q100L



Byte 0



content 0x00 K32_S

Byte 8 Byte 9



Read K41 Operation: ReadMemory bank: User MemoryWord Pointer: 0x1DWord Count: 5


Byte 0



content 0x00 K41_S

Byte 8 Byte 9






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ATLAS-Q100L


Byte 0



content 0x00 K42_S

Byte 8 Byte 9



Modify calibration parameters

The calibration words are stored inside the flash memory of the micro-controller included in the ATLAS-Q100L. Before writing anything in the flash, the previous content has to be erased. A calibration memory erase canbe triggered sending a standard write command pointing to the address 0x04 of the user bank. This triggers anerase of the whole calibration memory. It is not possible to erase calibration words independently.

Erase calibration memory Operation: WriteMemory bank: User MemoryWord Pointer: 0x04Data: do not care

Once the calibration memory has been erased, standard write commands can be used to write the calibrationparameters. However, given the characteristics of the SPI bridge, only 1 byte can be written with each writecommand. As the EPC standard word length is 2bytes, the byte to be written has to be sent right aligned in thecommand.

Write register Operation: WriteMemory bank: User MemoryWord Pointer: register addressData: 1 byte of data (right aligned in 2byte length EPC word)

The addresses of each byte of the calibration words are:



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ATLAS-Q100L


Address Register

0x05 K11_XL

0x06 K11_L

0x07 K11_M

0x08 K11_S

0x09 K12_XL

0x0A K12_L

0x0B K12_M

0x0C K12_S

0x0D K21_XL

0x0E K21_L

0x0F K21_M

0x10 K21_S

0x11 K22_XL

0x12 K22_L

0x13 K22_M

0x14 K22_S

0x15 K31_XL

0x16 K31_L

0x17 K31_M

0x18 K31_S

0x19 K32_XL

0x1A K32_L

0x1B K32_M

0x1C K32_S

0x1D K41_XL

0x1E K41_L

0x1F K41_M

0x20 K41_S

0x21 K42_XL

0x22 K42_L

0x23 K42_M

0x24 K42_S


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ATLAS-Q100L


DEMO SOFTWAREDemonstration software to read and control the ATLAS-Q100L is available in the web. Download the latestsoftware and user guide at: http://www.farsens.com/software.php. Currently, the software is compatiblewith the following UHF RFID readers:

Fixed readers

• Alien ALR9900

• AMS Radon

• Caen Muon DevKit - RS232

• CSL CS203

• Impinj R420

• Thingmagic M6

• Thingmagic M6e DevKit6

• Motorola FX9500

• Motorola FX7400/FX7500

• Nordic ID Sampo

• Nordic ID Stix

• RF-Embedded PUR500U

• Sirit IN610

Handheld readers

• Nordic ID Merlin

• Nordic ID Morphic

• Motorola MC9090G

• Motorola MC9190Z



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ATLAS-Q100L


REFERENCESThe next table shows the available references of the ATLAS-Q100L.

Ref. Name Description

34702 ATLAS-Q100L-MKS ATLAS-Q100L, meander wideband antenna, PCB format

For custom references with other antennas and housings, please contact us at [email protected].


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ATLAS-Q100L


MECHANICAL DIMENSIONSAll dimensions are in millimeters.

MKS

Valid for reference(s): 34702

COLOGO

COQuad V0Meter

Maximum height: 10mm

FX1901

The mechanical dimensions of the FX1901 transducer are as follows:



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EPC C1G2 COMPLIANT BATTERYLESS QUAD 45KGF COMPRESSION LOAD ...

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