493
Analog I/O Units
Section 9-4
(5) Refer to the following diagram regarding wiring disconnections when volt-
age input is being used.
Example: If analog input device 2 is outputting 5 V and the same power
supply is being used for both devices as shown above, approximately 1/
3, or 1.6 V, will be applied to the input for input device 1.
If a wiring disconnection occurs when voltage input is being used, the
situation described below will result. Either separate the power supplies
for the connected devices, or use an isolator for each input.
If the same power supply is being used by the connected devices and a
disconnection occurs at points A or B in the above diagram, an
unwanted circuit path will occur as shown along the dotted line in the
diagram. If that occurs, a voltage of approximately 1/3 to 1/2 of the out-
put voltage of the other connected device will be generated. If that volt-
age is generated while the setting is for 1 to 5 V, open-circuit detection
may not be possible. Also, if a disconnection occurs at point C in the dia-
gram, the negative (-) side will be used in for both devices and open-cir-
cuit detection will not be possible.
This problem will not occur for current inputs even if the same power
supply is used.
(6) When external power is supplied (when setting the range code), or when
there is a power interruption, pulse-form analog output of up to 1 ms may
be generated. If this causes problems with operation, take countermea-
sures such as those suggested below.
• Turn ON the power supply for the CP1L-EL/EM CPU Unit first, and
then turn ON the power supply for the load after confirming correct
operation.
• Turn OFF the power supply for the load before turning OFF the power
supply for the CP1L-EL/EM CPU Unit.
24 VDC
A
C
B
Analog
input
device 1
Analog
input
device 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...
Page 855: ......