EN
AC1256 Installation Manual
Product Description
The AC1256 is a DIN-rail mountable single-phase-input power supply, which provides network power
for the AS-Interface
®
system. The AS-Interface
®
system is a field bus technology, where power and
data are provided by the same single two-conductor wire. Therefore, special power supplies with an
integrated data-decoupling circuit are required to prevent the modulated signal voltage on the AS-
Interface
®
bus from being corrupted.
The output of the device fulfils the requirements for a limited power source according to NEC Class 2.
Intended Use
This device is designed for installation in an enclosure and is intended for commercial use to supply
power to AS-Interface
®
network systems.
Do not use this device in equipment, where malfunctioning may cause severe personal injury or
threaten human life without additional appropriate safety devices, that are suited for the end-
application.
If this device is used in a manner outside of its specification, the protection provided by the device may
be impaired.
When operating without AS-Interface structure (e.g. in a laboratory test), connect a 470μF/35V
capacitor between AS-Int and AS-Interface – terminals to avoid output voltage oscillations.
If this device is used in a manner outside of its specification, the protection provided by the device may
be impaired.
Without additional measures to reduce the harmonic input current (PFC), the power supply is not
suited to be connected to the public mains system in residential, commercial and light-industrial
environments. No additional measures are necessary for use in industrial environments. Exceptions
for various countries outside the European Union exist and can be determined locally.
Installation Instructions
Install device in an enclosure providing protection against electrical, mechanical and fire hazards.
Install the device onto a DIN-rail according to EN 60715 with the input terminals on the bottom of the
device.
Make sure that the wiring is correct by following all local and national codes. Use appropriate copper
cables that are designed for a minimum operating temperature of 60°C for ambient temperatures up to
+45°C, 75°C for ambient temperatures up to +60°C and 90°C for ambient temperatures up to +70°C.
Ensure that all strands of a stranded wire enter the terminal connection. Use ferrules for wires on the
input terminals. Unused screw terminals should be securely tightened.
The device is designed for pollution degree 2 areas in controlled environments. No condensation or
frost is allowed.
The enclosure of the device provides a degree of protection of IP20.
The housing does not provide
protection against spilled liquids.
The device is designed for overvoltage category II zones. Below 2000m altitude the device is tested
for impulse withstand voltages up to 4kV, which corresponds to OVC III according to IEC 60664-1.
The device is designed as “Class of Protection I” equipment according to IEC 61140. Do not use
without a proper PE (Protective Earth) connection.
The device is suitable to be supplied from TN, TT and IT mains networks. The continuous voltage
between the input terminals and the PE potential must not exceed 300Vac.
A disconnecting means shall be provided for the input of the device.
The device is designed for convection cooling and does not require an external fan. Do not obstruct
airflow and do not cover ventilation grid!
The device is designed for altitudes up to 5000m (16400ft). Above 2000m (6560ft) a reduction in
output current is required.
Keep the following minimum installation clearances: 40mm on top, 20mm on the bottom, 5mm left and
right side. Increase the 5mm to 15mm in case the adjacent device is a heat source. When the device
is permanently loaded with less than 50%, the 5mm can be reduced to zero.
The device is designed, tested and approved for branch circuits up to 20A without additional protection
device. If an external fuse is utilized, do not use circuit breakers smaller than 10A B- or 6A C-
Characteristic to avoid a nuisance tripping of the circuit breaker.
The maximum surrounding air temperature is +70°C (+158°F). The operational temperature is the
same as the ambient or surrounding air temperature and is defined 2cm below the device.
The device is designed to operate in areas between 5% and 95% relative humidity.
Functional Description
The output is electronically protected against no-load, overload and short circuit.
The green AS-i-OK LED reports a nominal output voltage of a running device. The LED is off as soon
as the unit is in overload mode.
The device is equipped with an over-temperature protection. In case of a high temperature, the output
shuts down and starts automatically again after cooling off.
Do not parallel devices for higher output currents.
Do not connect outputs of devices in a series connection for higher output voltages.
In case of an internal defect, a redundant circuit limits the maximum output voltage to 36V. The output
shuts down and automatically attempts to restart.
Technical Data
All values are typical figures specified at 230Vac 50Hz input voltage, 30.6V
2.8A output load, 25°C ambient temperature and after a 5 minutes run-in
time unless otherwise noted.
Output voltage
DC 30.6V
Nominal
Adjustment range
Not adjustable
Factory setting 30.6V
Output current
2.8A
Below +70°C ambient
For use on AS-Interface
®
networks only
Current limitation
>2.9A
Input voltage AC
AC 100-120V /
200-240V
±10%, auto select
Mains frequency
50 – 60Hz
±6%
Input current AC
1.44 / 0.86A
At 120 / 230Vac
Power factor
0.56 / 0.47
At 120 / 230Vac
Input inrush current
3 / 3A pk
At 120 / 230Vac, temp.
independent
Efficiency
86.9 / 88.0%
At 120 / 230Vac
Power losses
12.9 / 11.6W
At 120 / 230Vac
Hold-up time
98 / 96ms
At 120 / 230Va
Temperature range
-25 to +70°C
Max. wire size (litz wire)
4mm²
Wire size AWG
AWG 20-10
Max. wire diameter
2.8mm
Wire stripping length
7mm / 0.28inch
Tightening torque
1Nm / 9lb.inch
Size
(wxhxd)
40x124x120mm
Without DIN-rail
Weight
540g / 1.19lb
Functional Diagram
Input
Fuse
&
Input
Filter
L
N
Output
Overvoltage
Protection
Input
Rectifier
&
Inrush
Limiter
AS-i +
Output
Filter
AS-i-ok
(green)
Power
Converter
Shield
AS-i
Decoupling
Unit
AS-i +
AS-i -
AS-i -
115/230V
Auto
Select
Temperature
Shut-down
Output
Current
Limiter
Output Characteristic
Output voltage
Output current
15V
0V
1A
2A
4A
0A
30.6V
5A
3A
Temperature Range
Allowed output current
Ambient temperature
0A
-25
2.8A
+70°C
0
