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Q. Where can I find the last Firmware/Software version for my reader?
A. You can download the last firmware/software version for your reader on our download area at http://www.caen.it/rfid/download.php clicking on the respective link.
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Q. How does the communication with the host computer work? Does the reader give the computer the different IDs he received?
A. Together with our readers we provide libraries for the most used programming languages (C/C++, .NET and Java). For example, in order to read the IDs seen by the reader at a given time, you only need to call a function (InventoryTag) that returns an array of IDs. The libraries hide the details of the host-to-reader binary protocol.
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Q. Where can I download the protocol specifications and the CAENRFIDlib manual?
A. The protocol specification and the CAENRFIDlib manual are available for download at our website at the Download Area http://www.caen.it/rfid/download.php.
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Q. I’m using an RS232/USB converter, how can I connect the reader to the “CAEN RFID demo”?
A. The USB-RS232 converter creates a virtual serial port so you can think to the USB port as a standard COM port. To talk with the reader you must select the RS232 choice on our CAEN demo and enter the COM port number (i.e. type “COMx” where x is the port number where your driver has mapped the virtual port).
To know the port number where your driver has mapped the virtual port follow these steps:
1. Click Start —> Control Panel/System
2: When the System Properties window appears, click the Hardware tab
3: In the Hardware tab, click Device Manager
4: In the Device Manager, double click the COM PORT
5: See which ports are available. Usually COM1 is used for the true serial port. The other port should be the virtual port.
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Q. How can I connect the A829 reader to the CAEN RFID demo?
A. You just have to select the RS232 option on our CAEN demo and enter the COM port number (i.e. type “COMx” where x is the port number where your driver has mapped the virtual port).
To know the port number where your driver has mapped the virtual port follow these steps:
1. Click Start —> Control Panel/System
2: When the System Properties window appears, click the Hardware tab
3: In the Hardware tab, click Device Manager
4: In the Device Manager, double click the COM PORT
5: See which ports are available. Usually COM1 is used for the true serial port. The other port should be the virtual port.
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Q. Which is the difference between the Linear polarized and the Circular polarized Antenna?
A. Electric and magnetic fields radiated by linear polarized antenna are oriented along only one direction, on the contrary for circular polarized antenna EM fields rotate by tracing a circle perpendicular to the propagation direction.
A RFID tag is usually linear polarized, so with a linear polarized antenna the tag must be oriented in the same direction of the antenna. With a circular polarized antenna the tag can be oriented in any direction with respect to the antenna, even if only half of the radiated power density will be received by the tag. For this reason, with the same conducted input power, the ERP (Effective Radiated Power) of a circular polarized antenna is 3dB lower than the ERP of a linear polarized antenna that has the same gain (expressed in dBi).
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Q. How is the output power expressed in your Demo software? How is computed the radiate output power according to the antenna gain and cable loss?
A. Regarding the power settings, all of our demo applications require to insert the effective radiate power in mW ERP (Perp) that is related to the conducted RF power (Pw) provided at the reader's connector by the following formula:
where G is the antenna Gain expressed in dBi and L the cable attenuation expressed in dB.
The RF power to be set in the reader (Pw) in order to radiate the desired ERP power (Perp) is calculated by the software itself according to the above formula, then the calculated value is sent to the reader.
In particular for both CAEN RFID Show and CAEN RFID Java demo you shall insert the antenna gain expressed in dBi (for linear antennas) or dBic (for circular antennas) and the type of antenna you are using (circular or linear).
Please note that sometimes antenna manufacturers provides the gain of a circular antenna expressed in dBi. In this case you shall consider the antenna as a linear one and insert into the gain field this value (i.e. if antenna gain is 6dBi you shall enter gain=6 and type of antenna "linear"). As an alternative you can set the antenna as "circular" and increase by 3 the gain in dBi (i.e. if antenna gain is 6dBi you shall enter gain=9 and type of antenna "circular").
For CAEN Rfid Test program there is no antenna type setting so you shall operate as follows:
- If the antenna is linear you shall enter the gain expressed in dBi.
- If the antenna is circular and its gain is expressed in dBic you shall enter the gain decreased by 3.
- If the antenna is circular and its gain is expressed in dBi you shall enter the gain in dBi without any subctraction.
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Q. Which are the minimum and maximum values that we can use to set the output power in the CAEN RFID Demo software?
A. The value expressed in the CAEN RFID Demo software is the desired radiated power (ERP), so its real value depends on the antenna, the cable and the reader you are using. Anyway the maximum value you set should not overcome that one allowed by your country regulations.
According to European regulation ETSI EN 302-208 the maximum allowed radiated power is 2W ERP, according to U.S. regulation FCC part 15 is 4W EIRP equivalent to 2.44W ERP.
For the minimum radiated power values, please refer to the minimum power available for each CAEN RFID reader.
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Q. Which is the output power value available at the reader’s connector?
A. Please refer to the following table to know the output power available at your reader’s connector:
| A828 |
: 50 mW - fixed |
| A828A |
: 60 mW and 200 mW (only these two values are available) |
| A949 |
: 60 mW - 1.2 W programmable in 256 steps |
| A941EU |
: 60 mW - 1.5 W programmable in 256 steps (for both IP65 and OEM version) |
| A941US |
: 60 mW - 1W programmable in 256 steps (for both IP65 and OEM version) |
| A928 |
: 60 mW - 630 mW programmable in 256 steps |
| A948EU |
: 60 mW - 1.5 W programmable in 256 steps |
| A948US |
: 60 mW - 1W programmable in 256 steps |
| A528 |
: 10 mW - 500mW programmable in 8 step |
The A829 reader is composed of the A828EU reader plus a linear polarized antenna with a gain of 3dBi all enclosed in a plastic box. The radiated output power for this reader is approximately 60 mW ERP.
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Q. How is the output power expressed in your library functions?
A. Power settings in library functions are expressed in mW conducted at reader connector. In order to set the conducted power that generates the desired effective radiate power you shall apply the same formula used in our demo software (please see the relevant FAQ).
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Q. Using the readers with 4 antennas, is there the possibility to check which antenna has detected the tag?
A. You can identify via software which antenna has detected the tag either using the log file generated by our demo application or developing your own application using the libraries we provide.
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Q. Can I switch on/off the antennas in a selective way?
A. Yes, you can do it either using our demo applications or developing your own application using the libraries we provide.
Q. How can I use the Digital I/O in your large sized readers? Which is the meaning of the GP I/O pins?
A. Our large sized readers (A928 and A948) are provided with 4 General Purpose Input pins (1,2,3,4) and 4 General Purpose Output pins (5,6,7,8). Pins from 9 to 15 (included) are ground pins.
The GPO are “Open Collector” kind and can be powered up with a DC <= 25 Volt.
For what concerns the GPI they are normal TTL optically isolated input pin.
The I/O can be managed using the “Java Demo” provided with the development kit.
In case of using the libraries, you can refer to the below table for the mapping between the GPI/GPO pin and the bit of the SetlO() function;
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7
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6
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5
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4
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3
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2
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1
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0
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GPO3
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GPO2
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GPO1
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GPO0
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GPI3
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GPI2
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GPI1
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GPI0
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When the output bit is set to 1 the transistor corresponding to relative GPO is active (closed circuit) while when is set to 0 is inactive (open circuit).
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Q. Which is the reading range of your readers?
A. There is not a standard reply to this question since the reading range strongly depends on a large number of factors such as the tag, the antenna with its cable, the tagged material and last but not least the testing environment. A typical value for our readers (medium and large sized) combined with the antennas, cables and A918 tags we provide with the kits is 5-6 m. This value can significantly drop down in an hostile environment or grow up in a favourable condition.
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Q. How can I read the A927 Temperature logger UHF semi-passive tag using your CAEN RFID Demo software?
A. In order to read the A927 tag, you have to use the Java Demo software, taking care to select the IS018000-6B protocol and to set the bitrate (using the set modulation button) to the TX10RX40 instead of the default TX40RX40 value. After performing an inventory round you have to select the ID of the tag and go to the features menu —> ISO 18000-6b —> Read/Write. You should see a termometer icon on the window that gives you the access to the temperature logger. For more details please refer to par. 2.7 of the EASY2READ® DEMO software manual downloadable from http://www.caen.it/rfid/download.php
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Q. What can I do in order to connect my reader to the Java Demo though the serial port? Why using the serial port I’m not able to connect my reader to the Java Demo?
A. Unfortunately Java language does not provide a native support for the serial ports so we have to use a third-part library for that purpose. We have chosen the RXTX library that seems to be the most adopted. You can download the RS232 Java support at: http://users.frii.com/jarvi/rxtx and follow the installation instructions on the RXTX website in order to correctly install the library. By the way the archive contains the driver for many platforms; under windows the important files are:
Windows/i368-mingw32/rxtxParallel.dll
Windows/i368-mingw32/rxtxSerial.dll
RXTXcomm.jar
to install to RS232 support you have to copy:
rxtxParallel.dll and rxtxSerial.dll under the folder \jre\bin
RXTXcomm.jar under the folder \jre\lib\ext and \jre\lib
If you have to develop your own application using for example Netbeans, you have to copy this files also under the jre folder inside your Java jdk folder. If you forget to copy it, you can run your application without problem but you cannot debug it (it doesn't find the serial communication if you run it inside Netbeans).
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Q. Is it possible to configure the reader in order to read tag's IDs autonomously?
A. It depends on the reader you are using. At present only the A928 and A948 readers have this functionality; it is called "Asynchronous Mode". A complete description of this operational method is included inside the EASY2READ® DEMO software manual downloadable from http://www.caen.it/rfid/download.php.
All other models don't support the “Asynchronous Mode” so, in order to get the IDs, an explicit call to the InventoryTag function/method is needed.
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Q. Is it possible to lock the information inside a EPC Gen2 tag's memory?
A. You can use the Gen2 Lock function/method of our library which requires a parameter called payload. The meaning of the bit in the paylod parameter required by the lock command is as follow:
Each bit set to 1 in the MASK field allows you to write the bit of the corresponding ACTION FIELD (for example if you set to 1 the bit 19 of the KILL MASK you will be able to write to 0 or 1 the bit 9 of the KILL ACTION field); each bit set to 0 in the MASK field masks the write operation in the corresponding ACTION FIELD.
The two bits of the EPC, TID and USER ACTION field mean the following:
For example if you are using a payload value of 0x0C030, this should permanently prevent of writing the EPC code. In the case of tags that implement the USER memory, the value 0x00C02 should make the USER memory writeable only from the secured state but not from the open state.
Another example: the payload value 0xC0200 makes the KILL memory word not readable or writeable from the open state, while you can read or write it from the SECURE state.
A tag that has the ACCESS word memory set to 0x00000000 (default condition) is always in the secured state and cannot be killed.
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Q. Is there a way to put a customer password in order to read the EPC C1G2 data?
A. The EPC code in Gen2 tags is in a read/write memory bank. There is the way to lock it, both temporarily or permanently, but unfortunately the Gen2 protocol does not provide a way to protect EPC code from reading. It can be protected only for writing as well as the User and TID memory bank. You can only protect from unwanted reading the Kill and the Access password.To have more details on the protect/locking features of Gen2 protocol please take a look in the Gen2 protocol specification (starting from chapter 6) available at http://www.epcglobalinc.org/standards/
All the features explained in the protocol specification about protect/locking are implemented on our readers using Read, Write and Lock functions.
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Q. The led on the A949/A941’s power supply does not light on and I cannot connect the reader to the PC
A. There is no LED on the power supply; the object that seems a LED is a resistor used to configure the supplied voltage so it cannot light. The lack of communication between the reader and the PC could be due to other reasons, please take a look at the other FAQs.
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Q. How can I connect an external sensor to one of the general purpose I/O on my A948 reader? Is it possible to plug 24V directly, or do I need a voltage adaptation?
A. A948 GPI pins accept TTL levels.
If you want to drive them with a 24V signal you have to add a series resistor (i.e. 4.7kOhm) between the driver and the input pin.
For further details please see the following picture where the electrical interface of A948 GPI is shown: led inside optocoupler has a forward voltage of 1.15V and current through it should be from 2mA up to 10mA max.
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