CN1313944C - Intelligent transmitter device with embedded DeviceNet field bus interface - Google Patents

Abstract

The invention relates to an intelligent transmitter device embedded in a DeviceNet field bus interface. It includes a DSP transmitter circuit, which converts multi-parameters to be measured into high-precision digital quantities and performs processing operations; a power supply circuit, which converts the 24-volt power supply of the DeviceNet field bus (18) power line (10) into a 5-volt power supply , to provide DC power for each component of the transmitter device; it is characterized in that: the DSP transmitter circuit is connected to a DeviceNet bus interface circuit through a high-speed asynchronous serial port (5), and has a digital logic circuit and a DSP transmitter circuit Connect with DeviceNet bus interface circuit to realize LCD control, location decoding and button logic. This intelligent transmitter device can be connected to the standard DeviceNet field bus network, has high real-time data processing capability, and provides support for high intelligence; it has full digital field bus communication capabilities, remote monitoring, configuration and other functions; it has a powerful bus Power supply capability and communication anti-interference ability.

Description

Intelligent Transmitter Device Embedded in DeviceNet Fieldbus Interface

technical field

The invention relates to a sensor or a transmitter with a field bus interface, in particular to an intelligent transmitter device embedded in a DeviceNet field bus interface.

Background technique

In recent years, field bus has become the dominant system structure form of industrial process measurement and control system. Under the requirements of the fieldbus system structure, industrial process sensors and their instruments must be intelligent (including digitization and fieldbus). The integration of sensors and transmitters with CPU as the processing core and digital communication as the transmission mode is the fieldbus intelligent transmitter, also known as the networked transmitter.

The field bus intelligent transmitter requires the following characteristics: ① It can complete various complex calculations through the built-in high-performance processor and various application programs in the memory; it can perform different configurations through software; ② It has signal transmission, communication, There are three functions of power supply, which can realize 1-to-n transmitter wire connection and two-way communication; ③The electronic components adopt surface mount technology (SMT), design and select special circuit (ASIC) and microprocessor to realize small and light Quantify and improve reliability; ④ Real-time diagnosis and fault alarm can be performed without on-site repair and system maintenance.

At present, the HART protocol smart transmitter used by most instrument manufacturers is a "transitional" product. Although it already has some characteristics of fieldbus smart transmitters, the process data still uses 4-20mA analog signals. Digital signals can only perform limited functions such as device management and configuration, and do not have bus power supply capabilities. The network that can be established is small in scale, simple in structure, and poor in reliability.

On the other hand, it is always the wish of the majority of users to realize a unified and open fieldbus standard. As one of the field bus standards, CAN bus has the advantages of high reliability and low price compared with other buses. Machine tools, building automation, medical equipment, embedded network equipment, household equipment and sensors. However, the CAN protocol is a very simple protocol, which only defines the physical layer and the data link layer. As an incomplete bus bottom layer communication protocol, complex application issues such as communication between devices and systems need to be defined separately. Layer specification to achieve, which greatly limits its openness and versatility.

DeviceNet is one of the complete field bus protocol specifications based on CAN bus protocol specification supported by CiA, and it is also the bus international standard published by IEC. It connects basic industrial equipment (such as: limit switch, photoelectric sensor, valve group, variable frequency drive, material flow meter, etc.) While interchangeability reduces the cost and time of wiring and installing industrial automation equipment, its direct interconnection not only improves communication between devices, but also provides a very important device-level diagnostic function.

At present, there are many kinds of bus support in intelligent transmitters, such as FF, LonWorks, Profibus, etc., but there is no intelligent transmitter registered in ODVA's DeviceNet product catalog. In the domestic patent search, Zheda Zhongkong Technology Co., Ltd. submitted the invention patent on August 14, 2002 "transmitter capable of realizing Ethernet communication and powered by network redundancy" (application number: 01132306.X) A transmitter with Ethernet communication function and bus power supply capability is presented. The utility model patent "main circuit board of temperature/pressure sensor based on field bus" (application number: 02261659.4) submitted by the No. 711 Research Institute of China Shipbuilding Industry Corporation on November 18, 2002 provides a CAN The sensor circuit board device of the interface can realize the function of transmitting the processed digital signal to the CAN bus network, but it does not have the characteristics of the DeviceNet bus. In the published patent literature, there is no content related to the intelligent transmitter device with DeviceNet field bus function.

Contents of the invention

The object of the present invention is to provide an intelligent transmitter device embedded in a DeviceNet field bus interface capable of accessing a standard DeviceNet field bus network.

In order to achieve the above object, the present invention adopts the following technical solutions:

An intelligent transmitter device embedded in a DeviceNet field bus interface, including:

A DSP transmitter circuit, which converts the measured parameters into high-precision digital quantities and performs processing operations;

A power supply circuit, which converts the 24 volt power supply of the DeviceNet fieldbus power line to 5 volt power supply, and provides DC power for each component of the transmitter device;

It is characterized in that: the DSP transmitter circuit is connected to a DeviceNet bus interface circuit through a high-speed asynchronous serial port, and a digital logic circuit is connected with the DSP transmitter circuit and the DeviceNet bus interface circuit to realize LCD control and location decoding and key logic.

The circuit structure of the above-mentioned DSP transmitter is: a signal conditioning circuit interface is connected to a DSP processor through a multi-channel A/D converter and a voltage reference circuit, and a double-press keyboard and an LCD display are connected to the DSP processor; The A/D converter collects multiple parameters to be measured, converts them into 14-bit high-precision digital quantities, and sends them to the internal data storage of the DSP processor through the synchronous serial port of the DSP processor, and then performs processing operations.

The above-mentioned intelligent transmitter device embedded in the DeviceNet field bus interface is characterized in that the structure of the DeviceNet bus interface circuit is: a microprocessor connected to a DSP processor through a high-speed asynchronous serial port is connected to a DeviceNet module and a state two-color indicator circuit, a Watchdog chip, a static data storage and a non-volatile electrically erasable data storage, and connected to the communication line of the DeviceNet field bus through an independent CAN controller and CAV transceiver; the microprocessor implements the DeviceNet application layer Protocol, CAN controller and CAN transceiver implement physical layer and data link layer protocol.

The structure of the above-mentioned digital logic circuit is: a programmable logic device chip is respectively connected with a DSP processor, a microprocessor, a double-press keyboard, an LCD display, a static data storage and a CAN controller.

The 24-volt power supply of the power line of the above-mentioned DeviceNet field bus outputs 5-volt power supply for the internal digital circuit through an integrated regulated power supply module, and the other way enters a DC/DC isolation conversion module for multi-channel A/D converter and voltage reference Circuit and signal conditioning circuit interface power supply.

The invention realizes an intelligent transmitter device embedded with a DeviceNet communication function with bus power supply capability. Its outstanding advantages and effects are as follows: (1) Apply DSP processor to the field transmitter, use the powerful signal processing function of DSP to perform filtering, interference compensation, nonlinear correction, etc., so that the transmitter has high real-time Data processing capability, providing support for high intelligence; (2), embedded with integrated DeviceNet communication function, so that the transmitter has advanced all-digital fieldbus communication capability, remote monitoring, configuration and other functions; (3), due to the adoption of DeviceNet bus standard, using DeviceNet bus cables to provide power for sensors, conditioning circuits, signal processing circuits, and DeviceNet bus communication interface circuits, so that industrial field transmitters no longer have power consumption restrictions and excellent communication anti-interference capabilities.

Description of drawings

FIG. 1 is a schematic diagram of a hardware structure of an embodiment of the present invention.

Fig. 2 is a circuit schematic diagram of the power supply part of the embodiment of the present invention.

Fig. 3 is a main circuit diagram of the embodiment of the present invention.

Specific implementation method

A preferred example of the present invention is described in detail below in conjunction with accompanying drawing:

Referring to Fig. 1, the intelligent transmitter device with the DeviceNet field bus interface of the present embodiment includes a DSP transmitter circuit, a DeviceNet bus interface circuit, a digital logic circuit and a power supply circuit.

The DSP transmitter circuit includes: a signal conditioning circuit interface 1, a multi-channel A/D converter and its voltage reference circuit 2, a DSP processor 3, a double-press keyboard 11, and an LCD display 12. The multi-channel A/D conversion chip simultaneously collects temperature, static pressure, and differential pressure signals, converts them into 14-bit high-precision digital quantities, and sends them to the DSP internal data storage through the synchronous serial port of the DSP chip, and then adopts digital signal processing methods. The data fusion algorithm combined with the set configuration parameters can obtain the required static pressure value, differential pressure value, flow value or (and) liquid level value, density value, etc. The double-press keyboard 11 constitutes a local man-machine interface in the form of a single key and a combination key and a dot-matrix LCD. The display interface displays one or multiple result parameters selected by the user in the running state; displays configurable parameters in the form of a menu in the configuration state. The baud rate and slave station address related to DeviceNet are set by the software in the configuration menu through keys. The shutdown and reset of the DeviceNet network can be performed automatically when the relevant configuration information in the button menu changes.

Described DeviceNet bus interface circuit comprises: microprocessor 6, data memory 15, non-volatile electrically erasable data memory 16, watchdog chip 19, independent CAN controller 7, DeviceNet module and status two-color indicator light 14. CAN transceiver 17. The microprocessor 6 realizes the DeviceNet application layer protocol, and the independent CAN controller 7 and the CAN transceiver 17 connected with the microprocessor 6 realize the physical layer and the data link layer protocol. DSP processor 3 sends process real-time data to microprocessor 6 through full-duplex high-speed asynchronous serial port 5, and constitutes the I/O data of DeviceNet; ), and send them to the DSP processor 3 through the serial port.

Described digital logic circuit is realized by programmable logic device chip 13, is respectively connected with DSP processor 3, microprocessor 6, double keypad 11, LCD display 12, static data memory 15, CAN controller 7, realizes LCD control , address decoding, button logic, etc.

The power circuit is composed of an integrated regulated power supply module 8 and a DC/DC isolation conversion module 4 . The equipment is powered from the 24V power line 10 of the DeviceNet field bus 18, which first enters the integrated regulated power supply module 8, and outputs 5V power supply for internal digital circuits; the other enters the DC/DC isolation conversion module 4 for multi-channel A/D converter and voltage The reference circuit 2 and the signal conditioning circuit interface 1 supply power.

The communication between the above-mentioned DSP transmitter circuit and the DeviceNet bus interface circuit is connected through the high-speed asynchronous serial port 5, and its communication function features are: (1), two-way full-duplex data communication; (2), the communication frame is divided into data frames There are two types of data frames and information frames. The data frames contain the I/O data of DeviceNet about the application object instance of the transmitter. The information frames contain the device parameters set by the local man-machine interface, the DeviceNet network node parameters, and the control information of the DSP to the DeviceNet network. Support for displaying the parameter data of the report.

See Figure 3DSP transmitter circuit part (the lower half of the dotted line). DSP processor 3 adopts TMS320F206 of TI Company, AD converter part 2 adopts 14-bit four-channel AD conversion chip TLC3544 of TI Company and precise reference voltage output chip MAX875; LCD display 12 adopts 8×2 character dot matrix with HD44780 controller type display screen; the double-press keyboard 11 is connected with the DSP processor through the programmable logic device 13 shown in FIG. 3 .

The pins 1, 2, 3, and 5 of the AD converter part TLC3544 are respectively connected to the high-speed synchronous serial port pins 84-CLKR, 85-FSR, 90-DX, and 86-DR of the DSP processor 3, among which 84 and 87, 85 Short circuit with the 89 signal; the interrupt signal line 4 of the TLC3544 is connected to the interrupt 2 pin 19 of the DSP processor 3 through the pull-up resistor R8, and the interrupt trigger is used to notify the DSP of the end of the analog-to-digital conversion and the completion of data preparation. The analog power used for A/D conversion comes from the 0V output pin 5 and -5V output pin 7 of the DC/DC converter U19 of the power supply circuit 4 of the accompanying drawing 2; its analog reference power is connected to the output pin 6 of MAX875. The voltage input pin of MAX875 is connected to the +5V output pin 6 of the DC/DC converter U19 of the power supply circuit 4 of the accompanying drawing 2 .

The data lines 7-14 of the LCD interface are connected to the I/O port pins 22-31 of the DSP processor 3; the control signal RS is connected to the 32-pin I/O port; the read-write signal R/W is connected to the 47-pin; Terminal E is connected to pin 13 of the programmable logic device 13 in Fig. 3, and the signal is generated by the input signal pins 3, 4, and 5 of the programmable logic device 13; pins 15 and 16 are power supplies; pin 2 is the backlight brightness adjustment input .

The pins 76-82 of TMS320F206 are the JTAG interface of the DSP processor 3, which are connected to the port J2 for program burning and online programming debugging.

Referring to Fig. 3, DeviceNet bus interface circuit (half on the dotted line), microprocessor 6 selects the W78E58B of Winbond for use, has 32K program memory, uses 24MHz crystal oscillator; Data storage circuit 15 is made up of 74HC373 and 32KRAM high-speed memory, CAN controller 7 selects the SJA1000T of PHILIPS for use, selects the crystal oscillator 16MHz for use; CAN transceiver 17 selects the TJAi050T of PHILIPS for use, and watchdog circuit 19 selects the MAX813 chip for use; Nonvolatile electrically erasable data memory 16 selects the AT93C66 of Atmel for use, its CS, SK, The DI/O pins are respectively connected to the P1.5 P1.6 P1.7 ports of the microprocessor 6, and have 512 octets for storing node configuration information; the programmable logic device 13 selects GAL16V8D of Lattice to complete the logic decoding function.

The asynchronous serial ports 11 and 13 of the microprocessor 6 are connected with the 93 and 95 feet of the DSP processor 3 to form a dual-CPU data exchange channel; they are connected with the CAN controller U5 through a parallel port. The chip selection pin 4 of U5 is connected with the decoding output pin 12 of the programmable logic device 13, and the reset signal pin is connected with the 2 pin of the microprocessor 6. The output of U5 is connected to the input of U15, and then connected to the DeviceNet bus interface J2, and J2 uses the Sealed Mini connector in the DeviceNet protocol.

Referring to Figure 2, the power supply circuit is mainly composed of LM2576 integrated voltage regulator circuit U18 and its auxiliary circuits and DC/DC isolated power supply BB company's DCP010505DP positive and negative 5V output chip U19. The power supply circuit is supplied with 24V power by pins 1 and 5 of the bus connector J2. Transistor Q1 (2N391) and diode D4 (1N5819) form an anti-reverse connection and disconnection protection circuit. U18 integrates a regulated power supply module and C19, L1, D5, and C20 provide the power supply capability of outputting 5V and 3A, and L2 and C21 form a filter circuit. The U19 DC power isolation module outputs +/-5V, and its -5V output pin 7 is used as the analog ground to obtain the +5V analog power supply pin 5 and the +10V voltage reference module input pin 6.

Claims (5)

1. intelligent transmitter device that embeds the DeviceNet field-bus interface comprises:

A DSP transmitter circuit is converted to the high accuracy number amount and handles computing multiparameter is measured;

A power circuit is 5 volts of power supplys with 24 volts of power source conversion of DeviceNet fieldbus (18) power lead (10), for each assembly of transmitter device provides direct supply;

It is characterized in that: described DSP transmitter circuit connects a DeviceNet bus interface circuit by high-speed asynchronous serial ports (5), and have a DLC (digital logic circuit) to be connected with the DeviceNet bus interface circuit with the DSP transmitter circuit, realize LCD control, place decoding and button logic.

2. the intelligent transmitter device of embedding DeviceNet field-bus interface according to claim 1, it is characterized in that DSP transmitter circuit structure is: a signal conditioning circuit interface (1) connects a dsp processor (3) through a multi-channel a/d converter and voltage reference circuit (2), also has a double-key board (11) to be connected dsp processor (3) with a LCD display (12); It is measured that multi-channel a/d converter is gathered multiparameter, is converted to 14 high accuracy number amounts, and the synchronous serial interface by dsp processor (3) is sent to dsp processor (3) internal data reservoir, handles computing then.

3. the intelligent transmitter device of embedding DeviceNet field-bus interface according to claim 1 and 2, the structure that it is characterized in that the DeviceNet bus interface circuit is: a DeviceNet module of microprocessor (6) connection and a state bi-colour LED circuit (14) that connects dsp processor (3) by high-speed asynchronous serial ports (5), a watchdog chip (19), a static data reservoir (15) and a non-volatile electrically erasable data reservoir (16), and pass through a CAN controllers (7) is connected DeviceNet fieldbus (18) with CAV transceiver (17) order wire (9); Microprocessor (6) is realized DeviceNet application layer stipulations, and CAN controller (7) and CAN transceiver (17) are realized Physical layer and data link layer stipulations.

4. the intelligent transmitter device of embedding DeviceNet field-bus interface according to claim 3, it is characterized in that the structure of DLC (digital logic circuit) is: a programmable logic device (PLD) chip (13) is connected with dsp processor (3), microprocessor (6), double-key board (11), LCD display (12), static data reservoir (15) and CAN controller (7) respectively.

5. the intelligent transmitter device of embedding DeviceNet field-bus interface according to claim 3, the structure that it is characterized in that power circuit is: 24 volts of power supplys of the power lead (10) of DeviceNet fieldbus (18) are the internal digital circuit supply through 5 volts of power supplys of an integrated regulated power supply module (8) output, and another road enters a DC/DC isolation modular converter (4) and is multi-channel a/d converter and voltage reference circuit (2) and signal conditioning circuit interface (1) power supply.

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