Appendix E RS-485 Network E-
5
Appendix E
E. 2 Line Termination
Whenever the cable is long or the modules are different in the network,
signal reflections are very likely to occur. As a result, the quality of the
signals will be affected, and the signals will be distorted. In order to
eliminate this problem, a resistor should be implemented at the
beginning and the end of the cable.
Figure E-4 Signal Distortion
The value of the resistor should be as close as possible to the
characteristic impedance of the line. Although the receiving devices
will add some resistance to the transmission line, having the resistor
impedance equals to the characteristic impedance of the line should
be sufficient enough.
Example:
Each input of the receivers has a nominal input impedance of 18 kW
feeding into a diode transistor- resistor biasing network that is equivalent
to an 18 k
input resistor tied to a common mode voltage of
2.4 V. It is this configuration which provides the large common range
of the receiver required for RS-485 systems! (See Figure E-5 below).
Summary of Contents for ADAM 4100
Page 1: ...ADAM 4100 Industrial Grade Data Acquisition Modules User s Manual ...
Page 5: ...Introduction 1 ...
Page 9: ...Installation Guideline 2 ...
Page 24: ...I O Modules 3 ...
Page 25: ......
Page 37: ...Chapter 3 I O Modules 3 13 I O Modules Figure 3 10 Digital Output used with SSR ADAM 4150 ...
Page 40: ...Command Set 4 ...
Page 41: ......
Page 51: ......
Page 105: ...Calibration 5 ...
Page 109: ...5 4 ADAM 4100 Series User s Manual ...
Page 110: ...Utility Software A ...
Page 111: ......
Page 121: ...ADAM 4100 I O Modbus Mapping Table B ...
Page 131: ...Technical Diagrams C ...
Page 134: ...C 4 ADAM 4100 Series User s Manual Appendix C Figure C 3 DIN Rail Mounting ...
Page 136: ...C 6 ADAM 4100 Series User s Manual Appendix C Figure C 5 Panel Mounting ...
Page 138: ...Data Formats and I O Ranges D ...
Page 142: ...RS 485 Network E ...
Page 143: ......
Page 150: ...How to use the Checksum feature F ...
Page 154: ...Changing Configuration to Modbus Protocol G ...