Emerson ROC827 - Manual (Page 81)

ROC827 Instruction Manual
Issued Mar-06 Input/Output Modules 4-11
Caution
The Discrete Output module only operates with non-powered discrete
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.
+V
s
CONTROL
+
-
EXTERNALLY POWERED
DISCRETE DEVICE
+
-
-
COM
COM
COM
COM
COM
DO
2+
3 +
4 +
5 +
1+
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.
4.7 Discrete 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.
Representative
Internal Circuit Field Wiring