Rockwell Automation 1755-OF8 GuardPLC Controller Systems - Manual (Page 51)

Publication 1753-UM001C-EN-P - March 2010 51
Wire GuardPLC 1600, GuardPLC 1800, and GuardPLC 1200 Controllers Chapter 4
Safety-related Digital
Outputs The status of digital outputs is indicated via status indicators when the
controller or 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.
Safety-related Analog
Inputs GuardPLC 1800 controller analog inputs provide for the unipolar
measurement of voltages from 0…10V, referenced to L-. A 10 K
Ω
shunt is used for single-ended voltage signals. With a 500
Ω
shunt
resistor, currents from 0…20 mA can also be measured.
Analog cabling should be no more than 300 m (984 ft) in length. Use
shielded, twisted-pair cables, with the shields connected at one end,
for each measurement input. See the instructions for connecting
shielded cabling to the shield-contact plate on page
4 8 .
Unused analog inputs must be short-circuited. Place wire jumpers to
ground on any inputs that are not used.
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.
AI
T1 I1 L- T2 I2 L-
41 42 43 44 45 46
Wire Jumper Wire Jumper