Noise Cancellation Techniques

1. Noise Cancellation Techniques A presentation by Kaihatsu Techno Centre Pvt. Ltd. As a reference document for their customers Version 1.0, 2002 http://www.ktcpl.com This presentation is a property of Kaihatsu Techno Centre Pvt. Ltd. This is intended for the restricted use for the customers and prospective clients of Kaihatsu Techno Centre. This is a reference document only. The information given in this presentation is correct up-to the knowledge of the company. However this information is only for reference and can not be used by any one against Kaihatsu Techno Centre for any legal matters. The use of this document is only for general guidelines about selecting the best possible network link for his/her application. This presentation can not be considered for any loss of data or any other loss. This presentation must be utilised in full with total 9 pages. This presentation or the writer or Kaihatsu Techno Centre can be held responsible for any loss what so ever. The pricing given in this document may vary depending on the market situation. The pricing is given for comparison only and it should not be treated as an offer from Kaihatsu Techno Centre Pvt. Ltd. This presentation has 9 pages including this one. The figures, symbols and names used in this presentation is a trade mark property of respective individual or company. Reference Document

2. Topics in this Presentation • Following communication methods are addressed in this presentation. Click on the name to see the explanation of that mode. Analogue Voltage Channel RS 232 RS 485 Power Line Carrier Communication Radio Frequency Telephone End Reference Document

3. Analogue Voltage Channel • Use two pair shielded wire. Shield should be grounded at one point at source. Second point for shield should be left open. • Use resistor capacitor or pi circuit to filter the noise. • It is also recommended to use pull down resistor to cancel the noise. Reference Document

4. RS 232 C • Use nine shield core wire. • Wire should be as far from power line as possible. • Shield should be connected to instrument side chassis earth. Other side left open. • If instrument and PC are supporting use hardware flow control & even parity. • Reduce the baud rate. • Instrument baud parameters (baud rate, parity, flow control, stop & start bit) must be the same as that of PC software and PC port setting in control panel. Reference Document

5. RS 485 • Use twisted pair shielded wire. Min 7 twists in meter. • One end of the shield must be grounded to instrument and other left open. • Keep the wire away from power line. • At least one instrument or the PC must have termination resistor. • Use pull up and pull down resistor on both wires at least at one place in entire network. • Although limit is 32, do not connect more than 30 instruments on one line. • Note that baud rate is inversely proportional to distance. For more than 1,000 meters use very low baud rate like 300 bps. • Instrument baud parameters (baud rate, parity, flow control, stop & start bit) must be the same as that of PC software and PC port setting in control panel. • Do not interchange A & B (+/-) of the wire. All A’s (+) must be connected to A’s (+) only. • Check the instrument addresses. They should not clash. Reference Document

6. Power Line Carrier Communication • Phase, Neutral and Earth should be connected properly. • Use Low baud rate 300 bps • The other instruments used on the same power line must have proper noise filter. One can check this by switching them on one after other and determining when the PLCC communication fails. Reference Document

7. Radio Frequency • Use proper antenna, terminal wire and terminal connector. • The electrical line should be as fas as possible. • High voltage spike generating electrical fields should not be in a vicinity. • Use very good quality power supply. Specially designated for RF use. Reference Document

8. Telephone • Single strand twisted wire specially marked for telephone connection. • Do not use parallel connection. • Tune modem to match the impedance of the telephone exchange. • Avoid wire routine with power line line routes. • Use telephone connection box. Reference Document

9. Thank you.Property of Kaihatsu Techno Centre Pvt. Ltd. Quit Show This presentation is a property of Kaihatsu Techno Centre Pvt. Ltd. This is intended for the restricted use for the customers and prospective clients of Kaihatsu Techno Centre. This is a reference document only. The information given in this presentation is correct up-to the knowledge of the company. However this information is only for reference and can not be used by any one against Kaihatsu Techno Centre for any legal matters. The use of this document is only for general guidelines about selecting the best possible network link for his/her application. This presentation can not be considered for any loss of data or any other loss. This presentation must be utilised in full with total 9 pages. This presentation or the writer or Kaihatsu Techno Centre can be held responsible for any loss what so ever. The pricing given in this document may vary depending on the market situation. The pricing is given for comparison only and it should not be treated as an offer from Kaihatsu Techno Centre Pvt. Ltd. This presentation has 9 pages including this one. The figures, symbols and names used in this presentation is a trade mark property of respective individual or company. Reference Document