Emerson Comprehensive Guide to ROC827 Network Card Instruction Manual

	ROC827 Instruction Manual
	The Discrete Output module only operates with non-powered discrete
Caution
	devices, such as relay coils or solid-state switch inputs. Using the module
	with powered devices may cause improper operation or damage.

DO modules draw power for the active circuitry from the backplane, and are fused for protection against excessive current.

Note: When using the Discrete Output module to drive an inductive load (such as a relay coil), place a suppression diode across the input terminals to the load. This protects the module from the reverse Electro-Motive Force (EMF) spike generated when the inductive load is switched off.

Representative Internal Circuit

DO

Field Wiring

+Vs +

-

CONTROL

1+

COM

2+

COM

3 +

COM	DISCRETE DEVICE
4 +	- EXTERNALLY POWERED +
	-
COM

5+

COM

5 CHAN

DOC0508A

Figure 4-9. Discrete Output Module Field Wiring

Note: All I/O modules are isolated on the field side. Be aware that you can induce ground loops by tying commons from various modules together.

4.7Discrete Output Relay Modules

The five-channel DO Relay (DOR) module provides LEDs that light when each output is active. DOR modules use dual-state latching relays to provide a set of normally open, dry contacts capable of switching 2 A at

32 Volts dc across the complete operating temperature. You can configure the module as latched, toggled, momentary, or Timed Duration Outputs (TDO). The DOR can either retain the last value on reset or use a user- specified fail-safe value.

Figure 4-10 displays the field wiring connections to the output circuit of the DO Relay module.

Issued Mar-06 Input/Output Modules 4-11