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D-8
ADAM-5511
RS-485 Network
Thus as already stated above the line termination resistor R
T
will
normally equal the characteristic impedance Z
o
.
The star connection causes a multitude of these discontinuities since
there are several transmission lines and is therefore not recommend.
Note:
The recommend method wiring method, that causes
a minimum amount of reflection, is daisy chaining
where all receivers tapped from one transmission line
needs only to be terminated twice.
D.3 RS-485 Data Flow Control
The RS-485 standard uses a single pair of wires to send and receive
data. This line sharing requires some method to control the direction of
the data flow. RTS (Request To Send) and CTS (Clear To Send) are the
most commonly used methods.
Figure D-6:
RS-485 data flow control with RTS
Intelligent RS-485 Control
ADAM-4510 and ADAM-4520 are both equipped with an I/O circuit
which can automatically sense the direction of the data flow. No
handshaking with the host (like RTS, Request to Send) is necessary to
receive data and forward it in the correct direction. You can use any
software written for half-duplex RS-232 with an ADAM network
without modification. The RS-485 control is completely transparent to
the user.
Summary of Contents for ADAM-5511
Page 1: ...1 Introduction ...
Page 2: ......
Page 19: ...0 Quick Start Chapter ...
Page 35: ...1 Introduction Chapter ...
Page 39: ...2 System Specifications Chapter ...
Page 45: ...3 Installation Guidelines Chapter ...
Page 57: ...4 I O Modules Chapter ...
Page 110: ...4 54 ADAM 5511 I O Modules This page inyrntionally left blank ...
Page 111: ...5 Programming and Downloading Chapter ...
Page 143: ...6 Function Library Chapter ...
Page 153: ...ADAM 5511 6 11 Chapter 6 ADAMdelay 1000 WDT_clear WDT_disable Remarks None ...
Page 161: ...ADAM 5511 6 19 Chapter 6 SetRTCtime RTC_hour hour Remarks None ...
Page 163: ...ADAM 5511 6 21 Chapter 6 printf nNode number Error Remarks None ...
Page 169: ...ADAM 5511 6 27 Chapter 6 write_user_ram 0 Remarks None ...
Page 171: ...ADAM 5511 6 29 Chapter 6 Remarks None ...
Page 175: ...ADAM 5511 6 33 Chapter 6 Remarks None ...
Page 211: ...ADAM 5511 6 69 Chapter 6 Remarks None ...
Page 219: ...ADAM 5511 6 77 Chapter 6 Remarks None ...
Page 223: ...ADAM 5511 6 81 Chapter 6 printf start failed n Remarks None ...
Page 242: ...6 100 ADAM 5511 Function Library Remarks None ...
Page 244: ...6 102 ADAM 5511 Function Library Remarks None ...
Page 246: ...6 104 ADAM 5511 Function Library Remarks None ...
Page 248: ...6 106 ADAM 5511 Function Library Remarks None ...
Page 250: ...6 108 ADAM 5511 Function Library printf nAdam 4017 channel3 d data17 Remarks None ...
Page 252: ...6 110 ADAM 5511 Function Library printf nAdam 4018 channel3 d data18 Remarks None ...
Page 254: ...6 112 ADAM 5511 Function Library Remarks None ...
Page 260: ...6 118 ADAM 5511 Function Library printf nAdam 4080 channel2 d Idata80 Remarks None ...
Page 264: ...6 122 ADAM 5511 Function Library This page is blank ...
Page 297: ...A COM Port Register Structure Appendix ...
Page 301: ...B Data Formats and I O Ranges Appendix ...
Page 312: ...B 12 ADAM 5511 Data Formats and I O Ranges This page is blank ...
Page 313: ...C Examples on CD Appendix ...
Page 315: ...D RS 485 Network Appendix ...
Page 323: ...E Grounding Reference Appendix ...
Page 330: ...E 8 ADAM 5511 Grounding Reference Figure E 6 wire impedance ...