Baltech
If a supported Baltech RFID stand-alone device is used, the TwinCAT RFID library can be used as an interface. Alternatively certain Beckhoff Control Panels or Panel PCs can be used. In these devices an RFID reader can be integrated as an option. In this case an SDK containing the proprietary documentation is provided. The functionality if the TwinCAT library is the same in both cases.
RFID reader settings
For smooth communication between controller and RFID readers, some settings need to be made before the system startup. These include, for example, the baud rate for the serial communication. The proprietary tool "Baltech id-engine explorer" provided by the RFID reader manufacturer can be used to transfer these settings to the RFID reader. The tool can also be used to perform a function test to determine whether the RFID device and the transponder cards are recognized.
The following standard data transmission settings have been tried and tested:
Setting | Value |
|---|---|
Baud rate | 115200 baud |
Parity Bit | none |
Data bits | 8 |
Stop bit | 1 |
This matches the factory setting of the supported Baltech RFID devices. Other parameters can be set, if required. These must then also be adopted in the software reader connection (see RFID reader connection).
The baud rate of the readers can be changed with the tool "Baltech id-engine explorer" (see Baltech documentation: IdEngineExplorer.pdf).
The tool "Baltech id-engine explorer" only runs under Windows XP. It is not available for Windows CE. The baud rate is therefore not configurable under Windows CE.
In the PLC a fast task is required for processing the incoming data. When connecting the RFID device to a COM port and a baud rate of 115,200 baud, a cycle time of 1 ms is required (see RFID reader connection).
In order to configure the baud rate from the PLC, the following byte sequence can be transferred as a raw data block [ 0x 1C 00 09 06 00 01 03 00 02 xx xx - with xx xx representing the baud rate, e.g. 9600 baud: 96 units at 100 baud -> 0x 00 60 ]. Details are explained in section Low-level communication. This is also possible under Windows CE, if a transfer with the currently set baud rate is possible.
Using the virtual serial COM port (USB)
If the device is connected via USB, the appropriate USB-to-Virtual-Com-Port driver must be installed. If it is a Beckhoff Panel PC, the driver is already pre-installed. The SDK of the RFID device also contains the driver. The virtual COM port is displayed in the Windows Device Manager.
Communication to the driver takes place via Beckhoff TwinCAT serial communication. However, no corresponding device is created in the TwinCAT System Manager, and no link is established there. Further information can be found in the documentation for the PLC library "Serial Communication".
RFID reader handling
The library supports the standard settings for the Baltech communication. "Host Operation" mode is supported as "Operational Mode". Other modes are not supported. The BRP (Baltech Reader Protocol) is used for internal access in "Communication Mode" "Normal Mode". If raw data is sent via the low-level communication option, make sure that the above settings are correctly specified within the frame.
It must be pointed out here that not all peculiarities of every supported RFID reader model can be named here. Therefore you are referred to the manufacturer’s own documentation for more detailed information.
Configuration
If encrypted transponder cards are used, the same key must be available in the RFID device. The Baltech RFID reader is configured once, i.e. the key only has to be specified once. For security reasons the key cannot be read from the device configuration. In keeping with the encryption of a transponder card, a VHL file is stored in the device configuration. Several such VHL files can be stored in order to access different cards without the need for reconfiguration.
There are three ways to transfer such a VHL file into the configuration of the RFID device:
Configuration type | Description |
|---|---|
Configuration card | A configuration can be transferred via a configuration card. This is the preferred option. |
"Baltech id-engine explorer" tool | The tool can be used to transfer a configuration to the memory of the Baltech RFID device (see Baltech documentation: IdEngineExplorer.pdf). In simple cases the specific configuration can be created directly in the tool. Alternative Baltech offers technical support and can provide a file containing the configuration. The tool "Baltech id-engine explorer" runs on all Windows operating systems from Windows XP. It is not available for Windows CE. |
from the PLC | For Mifare Classic cards the transfer of a VHL file configuration can be programmed in the PLC program code. The command SetConfig transfers the configuration specified at the input in ST_RFID_ConfigIn. The structure of a Mifare card and the possible settings for key allocation are explained in ST_RFID_CfgStruct_BaltechMifVHLFile. (Detailed information about Mifare cards can be found in the Baltech document Mifare.pdf in the Baltech SDK) |
Transponders
Suitable transponder cards for Baltech RFID devices are available from several manufacturers. If cards with encryption are to be used, Baltech offers preconfigured cards for this purpose.