51 Research and Design, Electronic Engineers website - Embedded Systems, MCU, DSP, EDA, Test and Measurement, Components, Communications, Power, Microelectronics, Semiconductors

Introduction

In professions and so on electric power, steel and iron, petroleum, chemical industry, has the massive speed reducers, the air blower, the pumping station and so on mechanical device, if these equipment work in spite of one’s illness under the condition, will reduce its service life greatly, will affect the production, will bring the economic loss to the enterprise. In the tradition depends upon the staff ear to listen to the method discovery existence hidden danger which, the hand traces, the scene environment and the diagnosis experience’s restriction, will appear frequently leaks examines, the error diagnostic phenomenon. The identical Taiwan equipment’s two inspection time-gap is long, also does not favor the unusual circumstance the prompt discovery. Therefore, the factory online monitor appears very important.

The speed reducer is one of common actuation equipment, it works whether the unusual key parameter is: Vibration situation, bearing temperature, output speed of spindle, electrical machinery electric current, voltage and so on. Through the vibration signal, may know that gear meshing, transient equilibrium to be whether normal; Through the bearing temperature, may know that bearing’s gap, lubricates whether good; Through output shaft’s rotational speed and the electrical machinery electric current, may know whether to overload. The sub-station’s major function is the monitor, processing, the data upload, ultra limits the warning.

1.       Gross structure

The distributional supervisory system is generally arranges the master station in the monitoring center, arranges the sub-station in each monitoring point, connects through the bus structure the master station and the sub-station (Figure 1). After sub-station each sensor’s information acquisition processing, a part of important data demonstration on the sub-station’s graphic display device, will simultaneously possess the data gives the master station through the main line upload, after the master station each sub-station upload information analysis processing, to demonstrate that for the movement vision control supervisors, has realized to the wide range movement equipment’s online monitor.

The system uses Texas Instruments’s MSP430F149 to take the controller, chip realizes through SIMENS Corporation’s SPC3 with the PROFIBUS-DP bus interfacing. Selects the standard 4~20mA electric current signal output the oscillationpick-up, electrical machinery’s electric current, the voltage realizes the 0~3V output through the transformation. Installs the DS18B20 temperature sensor in the bearing location, realizes the countershaft warm monitoring (speed reducer work normal temperature for 50~60℃, generally rolling bearing work cannot surpass 95℃). On the output shaft installs the pulse output the tachometer generator. After MSP430F149 above will move signal gathering processing, demonstrated through LCD that simultaneously uploads the main line, reports this sub-station to the master station the movement condition.

2.       Related introduction

2.1 MSP430F149 micro controllers

MSP430F149 is one kind of ultra low power loss which, the composite signal 16 controllers TI Corporation produces, working voltage 1.8~3.6V. This monolithic integrated circuit has the rich periphery function, the internal integration multichannel 12 A/D switches, the hardware multiplier, 60KB Flash and 2KB RAM, the movement ambient temperature scope for - 40℃~ 85℃, may adapt to each kind of bad circumstances, very suitable achievement scene monitor terminal control unit.

2.2 PROFIBUS-DP field bus

PROFIBUS is one kind does not rely on the Manufacturer, the open style field bus, is at present internationally one of general field bus standards, by its unique technical characteristic, the strict authentication standard, the opening standard, the numerous manufacturer’s supports and develops the application guild regulations unceasingly, has been integrated field bus’s international standard IEC61158 and European standard EN50170, and is decided as in 2001 our country’s GB code JB/T10308.3-2001. PROFIBUS-DP (Decentralized Periphery, distributional auxiliary equipment) mainly uses in the automated system the unit cascade control system and the dispersion-like correspondence, uses 1st, 2nd with the user interface level, other 3~7 have not used, this kind of simplification’s structure has guaranteed the high speed data transmission.

2.3       SPC3 agreement special-purpose chip

The PROFIBUS-DP physics level is RS-485, but the communication protocol is quite complex. SPC3 is the SIEMENS Corporation’s special-purpose agreement chip, after using this chip, may put aside the complex agreement. SPC3 integrated DP in the agreement FDL level, because SPC3 integrated the complete DP main line agreement, therefore when corresponds with the master station, the monolithic integrated circuit uses the SPC3 chip likely to operate internal RAM, causes to reduce greatly from the station controller’s programming work load. The SPC3 safeguard text’s validity, may satisfy the entire text the uniform data exchange. The bus interface was the synchronized/asynchronous 8 connections which might parametrize, the interior integrated 1.5K pair of mouth RAM, entire RAM selected 8 byte section structure method, all needed to assign the address the BUF indicator, must aim at the section the opening. DP correspondence service access point by the SPC3 automatic establishment, what each kind of text information presents in front of the user is the different BUF internal data.

3.       System hardware design

System’s hardware mainly by the keyboard, the display module, the connection module, the system survey module is composed (Figure 2). Uses 3×3 the ranks scanning keyboard to be possible to save the I/O mouth greatly occupancy. 128×64 dot pattern LCD may demonstrate the massive information. In order to preserve some hypotheses the parameter and the performance data, selects serial storage chip 24LC02B which Microchip Corporation produces, it uses I ² C bus interface, composes at the same place take 256 bytes as the unit, the page writes the buffer to reach as high as 8 bytes, 1,000,000 times scratches writes. The connection module is composed of the SPC3 chip and the peripheral circuit, what because SPC3 uses is the 5V power supply, but MSP430F149 uses the 3.3V power supply, in the hardware design must consider that the 3.3V logical system and the 5V logical system coexistence, the component to adds to inputs the foot or outputs foot’s voltage usually is limited, these pins receive Vcc by the diode or the separative element, to avoid primary device’s damage and the data loss, uses the special-purpose level switch SN74LVCC4245A chip, it is 8bit the width bidirectional I/O level switch, BUS B is the 3.3V data, BUS A is 5V the data connection SPC3 chip, DIR determination data direction. SPC3 signal of stop X/INT after level switch sends in P1.6, raises for the monolithic integrated circuit arches the communication interrupt signal. In order to enhance the correspondence the anti-jamming, the SPC3 internal circuit must isolate with the physical interface on the electric appliance, uses high speed light pair HCPL7101 and the SN75ASL176D transceiver has safeguarded the PROFIBUS main line correspondence redundant reliability.

The axis warm survey uses single main line digital temperature survey chip DS18B20 which American DALLAS Corporation produces, working voltage 3.0V~5.5V, the temperature measurement scope for - 55℃~ 125℃, has the bus structure, may realize through P2.0 to 8 temperature sensor signal gathering.