Summary of RS485
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Rs485 modbus adapter for rvt touchscreen installation and start-up guide.
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2 – table of contents rs-485 table of contents 1 introduction .................................................................................................................. 4 1.1 intended audience ................................................................................................. 4...
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Rs-485 table of contents - 3 8.2 references .......................................................................................................... 22 8.3 adequate choice of an rs232-rs485 converter at the computer side .............. 22 contact us ...................................................
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4 – introduction rs-485 1 introduction 1.1 intended audience this manual is intended for installers, commissioning people, network managers who need to install an rs485 network, start or maintain a supervision system based on the modbus protocol. 1.2 before you start this manual describes the rs485 ...
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Rs-485 overview - 5 2 overview this chapter contains a short description of the modbus protocol and the rs485 interface. 2.1 introduction to modbus modbus is a serial, asynchronous protocol. The modbus protocol does not specify the physical interface. The typical physical interfaces are rs-232 and r...
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6 – serial interface considerations rs-485 3 serial interface considerations the modbus protocol communicates with the instrumentation by means of an industry standard serial interface. This interface may be rs-232, rs-422 or rs-485. Some systems may also support the protocol over other busses or ne...
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Rs485 serial interface considerations - 7 each signal that transmits in an rs-232 data transmission system appears on the interface connector as a voltage with reference to a signal ground. The rs-232 receiver typically operates within the voltage range of +3 to +12 and -3 to -12 volts. 3.4 rs-422 i...
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8 – serial interface considerations rs-485 3.8 shielding and grounding considerations the signal ground conductor is often overlooked when ordering cable. An extra twisted pair must be specified to have enough conductors to run a signal ground. A two-wire system then requires two twisted pairs. It i...
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Rs485 serial interface considerations - 9 various kind of rs485 to rs232 converters exists. To bridge the modbus network to another kind of software protocol, various kinds of protocol converters may be used. They are often called ‘protocol gateway: modbus to profibus, ethernet, can ….
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10 – rs485 modbus adapter rs485 4 rs485 modbus adapter the rs485 modbus adapter enables the connection of the controller to an rs485 modbus network. 4.1 main features the adapter is self powered through the power supply of the controller. Advantage: an external power supply is not needed. Advantage:...
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Rs485 rs485 modbus adapter - 11 57 mm fixing screw tx – rx led’s 48 mm 35 mm resistor termination switch extra depth to the controller max. 10 mm screwed terminal for bus cable connection 4.3 mounting the modbus adapter is specially shaped to fit the controller case and to plug into its dedicated co...
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12 – rs485 modbus adapter rs485 transient voltage suppressors screwed terminals on the rs485 side tx – rx led indication for easy debugging and troubleshooting slew-rate limited for error-free data transmission (minimizing emi and reducing reflections caused by improperly terminated cables) drivers ...
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Rs485 rs485 modbus adapter - 13 o communication - i/o configuration – com. Settings – modbus choose a slave address (the address must be unused in the modbus network it is inserted in) select the right communication speed (baud rate) select the right parity checking select the right number of stop b...
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14 – modbus protocol overview rs485 5 modbus protocol overview 5.1 overview modbus rtu is a non-proprietary serial communications protocol that is widely used in the process control industry. The protocol was developed by modicon for plc communications and later released for public use. This protoco...
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Rs485 modbus protocol overview - 15 5.2 data addresses in modbus messages modbus defines 4 address spaces: 2 address spaces for bit addressable data and 2 address spaces for 16 bits addressable data. Address space data readable/writable modbus name 0xxxx output bit read & write coil status 1xxxx inp...
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16 – data access rs-485 6 data access 6.1 access levels some access levels must be set to allow parameters to be changed. Here are some access levels used in the rvt. Set mode: the rvt must be in the set mode to allow parameter modifications. Locking switch: the locking switch has to be released ban...
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Rs485 troubleshooting - 17 7 troubleshooting 7.1 preferred method of testing in most cases the modbus master (usually a pc software package) will be running on a personal computer or on hardware which has rs232 communications ports. In these instances a converter will be needed to convert the rs232 ...
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18 – troubleshooting rs-485 connection of a ground wire and presence of a shielding will improve reliability. 7.4 check the transmit – receive indicators this is a convenient way to check the presence of tx – rx signals: the receive led (yellow led) indicates that a modbus query is being received by...
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Rs485 troubleshooting - 19 writings in the controller memory through modbus are restricted to a limited range applied on that data. An exception error is sent in case of a writing exceeding the allowed limited range of a data. 7.7 counters and loopback diagnostics modbus offers some interesting func...
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20 - appendix rs485 8 appendix 8.1 list of abbreviations ascii american standard code for information interchange baud rate unit for measuring transmission speed in bits/s; bit a binary digit, representing a one or zero bus an electrical circuit over which data is transmitted byte a whole number val...
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Rs485 appendix - 21 that information and functions are centered on aspect objects. Industrial it enabled a product that is industrial it enabled has been verified according to the process of industrial it certification. It has the right to use the “industrial it enabled” symbol. Loopback a test used...
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22 - appendix rs485 power it power factor controller rvt microprocessor based controller from the abb industrial controller range. The power it power factor controller rvt is intended to switch capacitor in order to compensate the power factor of the electrical network. Receive incoming communicatio...
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Rs485 appendix - 23 it shows the timings of the minimum silent length between the reception of a query and the transmission of an answer at different baud rate. Baud rate (bits/sec) minimum silent length (ms) 110 350 300 160 600 80 1200 40 2400 18.8 4800 9.5 9600 5.5 19200 3.4 38400 1.6 57600 1.6 th...
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Contact us ab b n.V. P ower quality p roducts avenue c entrale 10 zoning industriel de j umet b -6040 c harleroi (j umet), b elgium phone: +32(0) 71 250 811 fax: +32 (0) 71 344 007 e-mail: power.Quality@be.Abb.Com www.Abb.Com/lowvoltage © c op yr ig ht 2 01 1 a b b .2g c s 2150 13 a 005 0 - ju ne 2 ...