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Analog Input Units
Section 7-2
■
0 to 20 mA Inputs
■
4 to 20 mA Inputs
Averaging Function
For analog inputs, the averaging function operates when the averaging bit is
set to 1. The averaging function outputs the average (a moving average) of
the last eight input values as the converted value. If there is only a slight vari-
ation in inputs, it is handled by the averaging function as a smooth input.
The averaging function stores the average (a moving average) of the last eight
input values as the converted value. Use this function to smooth inputs that
vary at a short interval.
Open-circuit Detection
Function
The open-circuit detection function is activated when the input range is set to
1 to 5 V and the voltage drops below 0.8 V, or when the input range is set to 4
to 20 mA and the current drops below 3.2 mA. When the open-circuit detec-
tion function is activated, the converted data will be set to 8,000.
The time for enabling or clearing the open-circuit detection function is the
same as the time for converting the data. If the input returns to the convertible
range, the open-circuit detection is cleared automatically and the output
returns to the normal range.
Current in the 0 to 20 mA
range corresponds to hexa-
decimal values 0000 to 1770
(0 to 6,000). The range of
data that can be converted is
FED4 to 189C hex (-300 to
6,300). A negative current is
expressed as two’s comple-
ment.
Current in the 4 to 20 mA
range corresponds to hexa-
decimal values 0000 to 1770
(0 to 6,000). The range of
data that can be converted is
FED4 to 189C hex (-300 to
6,300). Current in the range of
3.2 to 4 mA is expressed as
two’s complement.
If an input is below the range
(i.e., less than 3.2 mA), the
open-circuit detection func-
tion is activated and the data
becomes 8,000.
0 mA
20 mA 21 mA
−
1 mA
Converted data
Hexadecimal (Decimal)
189C (6300)
1770 (6000)
0000 (0)
FED4 (
−
300)
Converted data
Hexadecimal (Decimal)
189C (6300)
1770 (6000)
0000 (0)
FED4 (
−
300)
4 mA
20 mA 20.8 mA
3.2 mA
0 mA
Summary of Contents for CP1H-CPU - 05-2006
Page 2: ...CP1H X40D CP1H XA40D CP1H Y20DT D CP1H CPU Unit Operation Manual Revised May 2006...
Page 3: ...iv...
Page 11: ...xii TABLE OF CONTENTS...
Page 15: ...xvi...
Page 19: ...xx...
Page 31: ...xxxii Conformance to EC Directives 6...
Page 71: ...40 Function Blocks Section 1 5...
Page 133: ...102 Computing the Cycle Time Section 2 7...
Page 169: ...138 CPM1A Expansion I O Unit Wiring Section 3 6...
Page 411: ...380 Clock Section 6 8...
Page 519: ...488 Replacing User serviceable Parts Section 10 2...
Page 527: ...496 Standard Models Appendix A...
Page 535: ...504 Dimensions Diagrams Appendix B...
Page 628: ...597 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Page 629: ...598 Connections to Serial Communications Option Boards Appendix F...
Page 659: ...628 PLC Setup Appendix G...
Page 665: ...634 Index work words 159 write protection 370...
Page 667: ...636 Revision History...