Woodward AtlasPC, Hardware Manual

Page: 40 / 134

AtlasPC Digital Control, Vol. I Manual 85586V1
32 Woodward
Discrete Inputs
The SmartCore board accepts 16 discrete inputs. Contact wetting voltage may
be supplied by the SmartCore card. Optionally, an external 18–28 Vdc power
source can be used to source the circuit wetting voltage.
Atlas
+24V
(isol)
17
1
18
Dry
Contact
GND
(isol)
Figure 5-9. Wiring Example–Discrete Input Interface to the SmartCore Board
Configuration Notes
•
Refer to Figure 5-9 for discrete input wiring.
•
The discrete input commons are tied together, so each SmartCore board
accepts only one voltage source, which can be internally or externally
supplied.
•
All contact inputs accept dry contacts.
•
If an external power supply is used, it must be rated to 28 Vdc max from
Class 2 type source for North America (SELV type source for applications
outside North America). Power supply outputs must be fused with
appropriately sized fuses (a maximum, current rating of 100
÷
V, where V is
the supply’s rated voltage, or 5 A, whichever is less).
•
The 24 V isolated contact power is protected by a 0.2 A poly switch. This
may not prevent interruption in control operation due to a short in the field
wiring, but should protect the control from damage. The poly switch will
reset itself when the short condition is resolved.