ABB AC 31 User Manual

Installation
ABB Control - AC 31 Page 4-11
1SBC 260400 R1001-b 06.99
2. Central unit and remote unit cabling
2.1. Power supply
Use rigid or multi-conductor AWG 14 (1.95 mm
2
) wires.
The connection of an external thermal fuse is necessary to provides material protection.
It is possible to select 230 V a.c. or 120 V a.c. with the selector switch situated underneath the
central units or extensible remote units. The products are delivered with the selector in the
230 V a.c. position.
An internal 24 V d.c. power supply is available on 120 / 230 V a.c. versions. This power supply
feeds the binary inputs of the unit and its extensions This internal power supply is protected
against short circuits and overloads. In the case of a short circuit or overload it is available 10
seconds after the fault elimination.
It is also possible to use an external 24 V d.c. power supply. In this case do not forget to
connect the earth of the external 24 V d.c. to that common to the inputs (terminal C).
2.2. Inputs/outputs cabling
Use rigid or multi-conductor AWG 18 (0.96 mm
2
) to AWG 14 (1.95 mm
2
) wires for inputs and
the rigid or multi-conductor AWG 14
(1.95 mm
2
) wires for the outputs.
- Input cabling: see Figure 4-12 to Figure 4-15. The common C of inputs has to be linked
to the 0 V or 24 V d.c. according to the sensor type.
- Output cabling: see Figure 4-16 and Figure 4-17.
2.3. Output protection
The relay outputs may be protected externally against parasites generated by an inductive
load with:
- a varistor or an RC module, in alternating current
- a free-wheel diode, in direct current
The presence of an external thermal fuse, connected to the common power supply of the
outputs, protects to the output connected devices.
The transistor outputs are protected internally against short circuits and overloads. However
with an inductive load, with L/R greater than 40 ms, it is necessary to add a free-wheel diode.
If an error occurs at one of the transistor outputs, it is indicated by the status of the central unit.
The presence of an external thermal fuse, connected to the common power supply of the
outputs, protects the output connected devices and also avoids unit damage should numerous
outputs overload.
Warning: In the case of the terminal O V is disconnected and in the same time the 24 V d.c. is
connected, the leakage current on output is 16 mA.

ABB AC 31 Specifications

General

Brand	ABB
Model	AC 31
Category	Controller
Language	English