98 Rockwell Automation Publication 450L-UM001D-EN-P - December 2019
Chapter 6 Installation and Wiring
Power Supply
The external voltage supply (+24V DC) must meet the requirements of
IEC61496-1. Give special attention to the following requirements:
• The power supply must bridge a short-term power failure of 20 ms
(according to IEC 60204-1).
• The maximum deviation of the voltage levels is 24V DC ±15%.
• The power supply is protected against overload (use NEC Class 2 or fuse
with 4 A in the 24VDC circuit).
• The light curtain devices must be provided with a 24V DC PELV or SELV
power supply that conforms to the requirements of 414-3 or IEC60364-4-
41. These provisions have been taken to confirm that, even if an internal
fault occurs, the voltage at the outgoing terminals cannot exceed 60V DC.
To comply with UL restrictions, GuardShield safety light curtain sticks are
powered by DC sources whose secondary circuits are isolated from the primary
circuit by double insulation or reinforced insulation. The DC power supply must
satisfy the requirements for National Electric Code (NEC) Class 2.
The following are Rockwell Automation power supplies that are NEC Class 2
and PELV compliant. They also meet the isolation and output hold-off time
requirements of two GuardShield safety light curtain transceiver sticks
(GuardShield safety light curtain outputs not loaded):
• 2080-PS120-240V AC
• 1606-XLP15E
• 1606-XLP30E
• 1606-XLP50E
• 1606-XLP50EZ
• 1606-XLP72E
• 1606-XLP95E
• 1606-XLSDNET4
Grounding
There are two types of recommended grounding for 450L safety light curtains:
• Protective earth (PE)
•Functional earth (FE)
Protective earth is intended to help protect personnel from electric shock.
Protective earth is also known as dirty earth as it can contain many types of noise
transients and stray currents. The 24V common side of the 24V power supply
must be connected to protective earth at one location.
To Next Page
Loading...