Rockwell Automation 440C Guardmaster 440C-CR30 Configurable Safety Relay User Manual - Manual (Page 23)

Rockwell Automation Publication 440C-UM001C-EN-P - November 2014 23
Power, Ground, and Wiring Chapter 3
Wire Output Devices Use Surge Suppressors
Because of the potentially high current surges that occur when switching
inductive load devices, such as motor starters and solenoids, the use of some type
of surge suppression to help protect and extend the operating life of the relays
output is required. By adding a suppression device directly across the coil of an
inductive device, you prolong the life of the outputs. You also reduce the effects
of voltage transients and electrical noise from radiating into adjacent systems.
The following diagram shows an output with a suppression device. We
recommend that you locate the suppression device as close as possible to the load
device. Since the outputs are 24V DC, we recommend 1N4001 (50V reverse
voltage) to 1N4007 (1000V reverse voltage) diodes for surge suppression for the
OSSD safety outputs, as shown in
Figure 8 . Connect the diode as close as
possible to the load coil.
Figure 8 - Surge Suppressors
Example suppressors include:
• 100-FSD250 for Bulletin 100S Contactors
• 1492-LD4DF terminal block with built-in 1N4007 diode
Embedded Serial Port Wiring The embedded serial port is a non-isolated RS-232 serial port that is targeted to
be used for short distances (<3 m) to devices such as HMIs (for example,
PanelView). Pin 2 and the shield are both internally connected to the -24V
Common (A2) terminal of the CR30.
The CR30 uses the minimal RS-232 connection; only transmit (TxD), receive
(RxD) and ground connections are required. The CR30 does not require nor
perform any handshaking, therefore the Request To Send (RTS), Clear To Send
(CTS), and Carrier Detect (DCD) are not used.
The CR30 only supports RS-232. The RS485 signals, which are used by some
products with the 8-pin mini DIN connector, are not used.
+24V DC
Diode
Surge
Suppressor
24 V Common
K1
12 A2 A1 13 14 15 16 17 18 19 20 21
Input/Output Terminal Block +DC
24V
COM
0V