Abstract: This article describes how to use a HIS protocol conversion gateway to achieve communication between a PROFIBUS fieldbus and a SICK barcode scanner serial communication network. Keywords: Fieldbus, PROFIBUS-DP, RS232, SICK Barcode Scanner, Protocol Conversion Gateway Abstract: This paper introduces how to use the Protocol Conversion Gateway to realize the communication between PROFIBUS field bus and SICK Barcode Scanner. Key words: FieldBus, PROFIBUS-DP, RS232, SICK Barcode Scanner, Protocol Conversion Gateway I. Introduction to Hilscher netTAP Gateway The Hilscher netTAP gateway supports the conversion of serial protocols (RS232/RS422/RS485) to fieldbus protocols or Ethernet protocols. Automatic conversion between the two different protocols can be achieved through simple configuration software. Protocol conversion includes: 1. Serial protocol to PROFIBUS slave station conversion; 2. Serial protocol to DeviceNet slave station conversion; 3. Serial protocol to CANopen slave station conversion; 4. Serial protocol to Ethernet protocol conversion. The serial protocol can be Modbus RTU, SIEMENS, etc. 3964R protocol, standard custom ASCII protocol; Ethernet protocol can be Modbus TCP protocol, standard TCP/IP protocol, or UDP protocol. II. NT30-DPS-RSI2 Gateway for Connecting SICK Barcode Scanners to a Profibus-DP Network The NT30-DPS-RSI2 model is a gateway that converts RS232 serial port protocol to Profibus slave protocol. NT30 represents the netTAP30 series, DPS represents Profibus-DP Slave, and RSI2 represents RS232 interface (where I represents port isolation). In this case, the SICK intelligent fixed 1D barcode scanner CLV430-0010 is used for scanning and reading EMS letter barcodes in the postal sorting system, equipped with a connection module CDB420-001 providing an RS232 communication interface. The actual control system uses a Siemens CPU315-2DP processor with an integrated PROFIBUS-DP master interface. Considering ease of wiring, programming, and system expansion, a gateway is chosen to connect the CLV430 to the PROFIBUS-DP network. The overall system structure diagram is as follows: III. Hardware Configuration in STEP7 Software : The NT30-DPS-RSI2 gateway operates as a slave on the PROFIBUS-DP network, therefore requiring the CPU315-2DP's input/output image area for data exchange. Two bytes of input and two bytes of output are fixed and necessary, used for controlling data reception and transmission (i.e., control words). Other input/output image areas are used to store received messages and messages to be sent; the appropriate image area size can be selected based on the protocol frame length during actual use. All netTAP serial-to-fieldbus gateways can be configured to operate in two modes: master mode and slave mode. In master mode, data frames are received first from the bus direction, while in slave mode, data frames are received first from the serial bus direction. In our case, when the CLV430 detects the barcode information of an EMS letter, it will automatically send a data frame. The CPU315-2DP only needs to continuously receive the barcode information from the CLV430; therefore, the gateway needs to operate in slave mode. The basic principle of a gateway in slave mode is as follows: 1. Data reception: When the gateway receives a data frame from the RS232 side, it will put the received complete data frame into the input image area. At the same time, it will invert the receive notification bit of the first byte of the control word of the input image area to notify the CPU that new data has arrived. The second byte of the control word stores the length of the received data frame in bytes. After the CPU finishes processing the received data (for example, backing up the data frame in the input area to the DB data block), it must make the value of the receive acknowledgment bit in the first byte of the output image area control word equal to the receive notification bit in the first byte of the input image area control word to confirm successful reception and notify the gateway to prepare for the next data reception. For STEP programming, add the following code to OB1: A Receive Notification Bit = Receive Acknowledgment Bit 2. Data Transmission: If the CPU315-2DP needs to send a data frame back to the serial port object after receiving data, simply put the transmitted information frame into the output image area, put the length of the transmitted data frame into the second byte of the output image area control word, and then invert the transmit notification bit in the first byte of the output image area control word. When the gateway detects that the values ​​of the transmit notification bit in the output image area control word and the transmit acknowledgment bit in the input image area control word are not equal, it will automatically send the information to the serial port object. After transmission, it will automatically set the value of the transmit acknowledgment bit in the input image area control word to be equal to the transmit notification bit in the output image area control word to notify the CPU that the information transmission is complete. For a detailed description of the gateway's working principle, please refer to the relevant documents on the CD. In this case study, the configuration of the STEP7 hardware is as follows: Open the Hardware section of STEP7, add the HIL_08EA.GSD and Hil_0916.gsd files from the GSD folder on the gateway's CD to the hardware library, then select the Profibus DP\Additional Field Devices\General\NT 30-DPS entry and drag it to the Profibus-DP network cable. Set its Profibus-DP address to 3, and configure 2 bytes of input (control word), 32 bytes of input (receive message area), 2 bytes of output (control word), and 32 bytes of output (transmit message area); as shown in the figure below: Note: Since the CPU in this case does not need to send data frames to the CLV430, the size of the output image area can be set smaller, as small as 1 byte. Specific settings can be selected in the gateway parameter configuration software SYCON.net. IV. Gateway Parameter Configuration The netTAP gateway uniformly uses the Hertz SYCON.net software for parameter configuration. Click SYCONnet netTAP setup.exe on the CD to install. Note: Before using the new gateway, you must first download the firmware via SYCON.net. For the NT30-DPS-RSI2 gateway, the CD contains three firmware versions: 1. ModbusRTU - ProfibusDP Salve; 2. 3964R - ProfibusDP Salve; 3. ASCII - ProfibusDP Salve. In this case, we choose the ASCII - ProfibusDP Salve firmware, with the firmware file NTDPSASC.N34. After downloading the firmware, configure the parameters. In addition to the default parameters, the following parameters need to be changed: 1. ASCII parameter page: Parity=none; Telegram timeout=50; Note: The message timeout parameter is only effective when End mode=only time control (default mode, using time control to determine the end of received data frames). Of course, if the serial port protocol has a clearly unique end character, then the end identifier mode can be used. The message timeout parameter is the time the gateway reserves to receive each serial data frame. For example, if the default value of 1000ms is used, after the gateway spends 30ms receiving a serial data frame, it will wait another 970ms before receiving the next serial data frame, ignoring all serial data frames in between. In this case, we set it to 50ms. Since each frame of data from the scanner is a fixed 18 bytes, the reception time at 9600 baud will not exceed 30ms. Therefore, a slightly larger setting of 50ms is chosen. 2. MODULES parameter page: Input/output image area size 2/32/2/32; Note: The configuration in STEP7 must be consistent with this parameter! After saving the parameters, download them to the gateway. Once the gateway and CPU315-2DP establish Profibus-DP communication, it enters the protocol conversion operation state. The following image shows the SYCON.net configuration interface: V. Case Application In this case, the correspondence between a certain EMS barcode and the received data is as follows: EMS Barcode: *EO824508219CN* Received Data (Hexadecimal): 02 20 45 4F 38 32 34 35 30 38 32 31 39 43 4E 0D 0A 03 The starting character is 02, 20 is a space character, and the ending character is 0D 0A 03. The middle part is 13 bytes of EMS barcode data, totaling 18 bytes. The character format in different applications is related to the SICK scanner communication parameter configuration. VI. Conclusion Fieldbus and industrial Ethernet networks are becoming increasingly prevalent in automation engineering, especially popular fieldbuses such as Profibus, DeviceNet, CANopen, and ModbusTCP, and industrial Ethernet, which are finding more and more applications. HISHUAN's netTAP series gateways play a crucial role in connecting intelligent devices with serial protocols, such as sensors and instruments, to fieldbus and industrial Ethernet, bringing significant convenience to users in system integration for network communication. Furthermore, HISHUAN's renowned European programmable PKV series gateways provide protocol data communication conversion functions from fieldbus masters to industrial Ethernet, offering more solutions for large-scale network communication between different protocols. We express our sincere gratitude to the China Representative Office of HISHUAN Automation Systems GmbH for their strong support. References [1] SICK barcode scanning system - automated identification technology (SICK Sensors GmbH, Germany). [2] Protocol conversion gateway technical manual - PROFIBUS (HERS Automation Systems GmbH, Germany) Author: Zhang Peng Male (1975-) Engineer Wuxi Beichen Automation Technology Co., Ltd. (HERS China East China Distributor) Wang Haibo Male (1982-) Engineer Wuxi Beichen Automation Technology Co., Ltd. (HERS China East China Distributor)