| Remote Pre-Processing in RFID Applications
Growing data requirements are increasingly overloading centralised control structures in applications, thus increasing the demand for decentralised approaches. RFID is a good example of this.
Although only a few bytes actually have to be evaluated from the tag, with centralised solutions all the data has to be transferred to the controller in order to filter out the user data.
With its first programmable gateway for the BL67 I/O system, TURCK now makes it possible to improve the time response of the entire system and reduce the volume of data on the network.
Thanks to the newly acquired “local intelligence”, the gateway considerably relieves the processing load of the higher-level controller since the entire handling of the sometimes complex RFID communication can now be handled locally in the gateway. The function block (“Proxy Ident Block”) required for the PLC is executed directly in the programmable gateway and the higher-level controller is sent only the user data it really needs.
This combination of programmable gateway and BL ident RFID system particularly enables the upgrading of existing systems in which “elderly” controllers still have to be used.
The BL67-PG-EN gateway is programmed in compliance with IEC 61131-3 using CoDeSys, a widely used programming software for controllers, displays, PCs and remote field devices. The standard programming languages LD (ladder diagram), FBD (function block diagram), IL (instruction list), ST (structured text) and SFC (sequential function chart) are available for the user.
The core of the new gateway is a powerful 32-bit RISC processor with a 512 Kbyte program memory that processes 1000 IL instructions in less than 1 ms. In addition to a 10/100 Mbit Ethernet interface, an RS232 interface is also provided. Compatibility with the standards of the CoDeSys Automation Alliance enables them to exchange data easily with other gateways or the devices of other suppliers in decentralised applications.
The entire range of expansion modules of the BL67 system is available for the I/O level of the programmable gateway. This allows a large number of signals present in an application to be processed directly by the control system. The gateway also provides the user program with direct write and read access to Modbus TCP registers which can be evaluated automatically via
Ethernet by a Modbus TCP slave task running in parallel. This function is particularly important when the communication partner used is not a CoDeSys device. Other versions of the programmable gateway are planned for the near future. Communication as PROFIBUS-DP slave or EtherNet/IP Adapter is planned as well as similar devices from the BL20 series for use in the control cabinet.
The programmable gateway for BL67 and the BL ident RFID system combine to form yet another dream team within the full TURCK range. As well as high temperature tags that can withstand temperatures up to 210 °C for 30 minutes, TURCK also offers standard tags as discs with diameters of 16, 20, 30 and 50 mm. The R20...R50 devices are available with EEPROM or FRAM memory.
The FRAM tags allow considerably faster processing than EEPROM tags and can be written 1010 times. Whilst the EEPROM tags are available with memories of 64 and 128 bytes, FRAMs are available with a memory of 2 Kbyte.
The write-read heads operate with air interfaces of between 20 and 200 mm depending on the combination of tag and write-read head used. They are integrated in industrial housings and also allow mixed operation: cylindrical M18 and M30, rectangular CK40 and Q80, as well as ring-shaped S32XL. Each write-read head is also able to process the different types of tags from the TURCK range: a write-read head for every tag regardless of whether an EEPROM or FRAM memory is used!
BL ident can be adapted optimally to any application thanks to its highly modular design with 2, 4, 6 or 8 channels. The PROFIBUS DP, DeviceNet™, Ethernet/IP, PROFINET IO and Modbus TCP fieldbus interfaces in addition to the programmable modules ensure maximum flexibility. BL ident can thus be integrated easily into existing systems without any problem – with protection to IP20 and IP67 using tested standard function modules.
The BL ident cables provide for simple and reliable connections. They ensure fault-free communication on the transfer path between the interface module and write-read head. A so-called graphical configurator enabling the right combination of write-read head and tag to be found easily for the application at hand completes the system. It is available free of charge at www.turck.com.