Safety-related digital outputs, Power supply connections – Rockwell Automation 1755-OF8 GuardPLC Controller Systems User Manual
Page 70
70
Publication 1753-UM001C-EN-P - March 2010
Chapter 6 Wire 1753-IB16, 1753-OB16, and 1753-IB20XOB8 Modules
Safety-related Digital
Outputs
The status of digital outputs is indicated via status indicators when the
module is in RUN mode.
GuardPLC outputs are rated to either 0.5 A or 1.0 A at an ambient
temperature of 60 °C (140 °F). At an ambient temperature of 50 °C
(122 °F), outputs rated at 1.0 A increase to 2.0 A.
If an overload occurs, the affected outputs are turned off. When the
overload is eliminated, the outputs are under the control of the
controller and are energized based on the user program code.
An output is in the safe state when it is de-energized. Therefore,
outputs are switched off when a fault that affects the safe control of
those outputs occurs.
For connection of a load, the reference pole L- of the corresponding
channel group must be used. Although L- poles are connected
internally to L- on the power supply input, it is strictly recommended
to connect the L- reference poles only to their corresponding output
group. EMC testing was performed in this manner.
Power Supply Connections
The supply voltage is connected via a 4-pin connector that
accommodates wire sizes up to 2.5 mm
2
(14 AWG). You only need to
connect one wire to L+ and one wire to L-. Both L+ and L- terminals
are internally connected. The other terminal can be used to
daisy-chain 24V DC to additional devices. The power supply
connector is rated to 10 A.
TIP
Inductive loads can be connected without a protection diode on
the load, because there is a protection diode located within the
GuardPLC device. However, Rockwell Automation strongly
recommends that a protection diode be fitted directly to the
load to suppress any interference voltage. A 1N4004 diode is
recommended.
ATTENTION
Before connecting the power supply, check for correct polarity,
value and ripple.
Do not reverse the L+ and L- terminals or damage to the
controller will result. There is no reverse polarity protection.