xxv
Safety Precautions
3
• The PLC will turn OFF all outputs when its self-diagnosis function detects
any error or when a severe failure alarm (FALS) instruction is executed.
Unexpected operation, however, may still occur for errors in the I/O control
section, errors in I/O memory, and errors that cannot be detected by the
self-diagnosis function. As a countermeasure for all these errors, external
safety measures must be provided to ensure safety in the system.
• The PLC or outputs may remain ON or OFF due to deposits on or burning
of the output relays, or destruction of the output transistors. As a counter-
measure for such problems, external safety measures must be provided
to ensure safety in the system.
• When the 24-V DC output (service power supply to the PLC) is over-
loaded or short-circuited, the voltage may drop and result in the outputs
being turned OFF. As a countermeasure for such problems, external
safety measures must be provided to ensure safety in the system.
!WARNING
Fail-safe measures must be taken by the customer to ensure safety in the
event of incorrect, missing, or abnormal signals caused by broken signal lines,
momentary power interruptions, or other causes. Not doing so may result in
serious accidents.
!WARNING
Do not apply the voltage/current outside the specified range to this unit. It may
cause a malfunction or fire.
!Caution
Execute online edit only after confirming that no adverse effects will be caused
by extending the cycle time. Otherwise, the input signals may not be readable.
!Caution
Confirm safety at the destination node before transferring a program to
another node or editing the I/O area. Doing either of these without confirming
safety may result in injury.
!Caution
Tighten the screws on the terminal block of the AC power supply to the torque
specified in this manual. The loose screws may result in burning or malfunction.
!Caution
Do not touch anywhere near the power supply parts or I/O terminals while the
power is ON, and immediately after turning OFF the power. The hot surface
may cause burn injury.
!Caution
Pay careful attention to the polarities (+/-) when wiring the DC power supply. A
wrong connection may cause malfunction of the system.
!Caution
When connecting the PLC to a computer or other peripheral device, either
ground the 0 V side of the external power supply or do not ground the external
power supply at all. Otherwise the external power supply may be shorted
depending on the connection methods of the peripheral device. DO NOT ground
the 24 V side of the external power supply, as shown in the following diagram.
24 V
0 V
0 V
Non-insulated DC power supply
0 V
Peripheral device
FG
FG
CPU Unit
FG
Twisted-pair
cable
FG
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: ......