467
Analog Input Units
Section 9-2
For example, if analog input device 2 is outputting 5 V and the same power
supply is being used as shown above, about 1/3, or 1.6 V, will be applied at
the input for input device 1.
Consider the following information on open input circuits when using voltage
inputs. Either use separate power supplies, or install an isolator at each input.
If the same power supply is used as shown in the following diagram and an
open circuit occurs at point A or B, an unwanted current flow will occur as
shown by the dotted lines in the diagram, creating a voltage at the other input
of about 1/3 to 1/2. If the 1 to 5 V range is being used, the open-circuit detec-
tion function will not operate. Also, if there is an open circuit at C, the open-cir-
cuit detection function will not operate because the negative sides are the
same.
Allocating I/O Words
Four input words and two output words are allocated from the next words fol-
lowing the last I/O words allocated to the CPU Unit or an existing Expansion
Unit or Expansion I/O Unit.
Writing Set Data
Write the settings for input use, averaging use, and range codes for words
n+1 and n+2. When the set data is transferred from the CPU Unit to the Ana-
log I/O Unit, the A/D conversion will be started.
A
C
B
Analog
output
device
1
Analog
output
device
2
24 VDC
3. Creating the Ladder Program
Words (m+1) to (m+4)
Analog Input Unit
Words (n+1), (n+2)
Summary of Contents for CP1L-EL20DR-D
Page 3: ...CP1L EL20D CP1L EM30D CP1L EM40D CP1L EL EM CPU Unit Operation Manual Produced July 2017...
Page 4: ...iv...
Page 10: ...x...
Page 22: ...xxii...
Page 34: ...xxxiv Software Licenses and Copyrights 7...
Page 192: ...158 Trial Operation and Debugging Section 5 3...
Page 250: ...216 Automatic Clock Adjustment and Specifying Servers by Host Name Section 6 7...
Page 666: ...632 Trouble Shooting Section 11 7...
Page 696: ...662 Standard Models Appendix A...
Page 805: ...771 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Page 806: ...772 Connections to Serial Communications Option Boards Appendix F...
Page 836: ...802 PLC Setup Appendix G...
Page 838: ...804 TCP Status Transitions Appendix H...
Page 840: ...806 Ethernet Network Parameters Appendix I...
Page 842: ...808 Buffer Configuration CP1L EL EM Appendix J...
Page 844: ...810 Ethernet Specifications Appendix K...
Page 851: ...Index 817 work words 118 write protection 447...
Page 852: ...818 Index...
Page 854: ...820 Revision History...
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