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Notes and explanations In 4 steps to the AS-i networkStep 1: Selection of the suitable power supplies. AS-i power supply For the voltage supply a special AS-i power supply must be used. In contrast to conventional power supplies it includes the necessary data decoupling.ifm supplies the units in different power classes. The required rating can bedetermined as follows:I

Generalinformation

=number of slaves x current consumption per slave (typ. 35 mA) + number of module inputs x max. input current typ. 5 mA + number of sensors x individual current consumption(e.g.10 mA / inductive sensor, 35 mA / photoelectric sensor)+ current for master analogue part (typ. 60 mA) + 10% safety margin (e.g. for heating)The current consumption for each slave is stated on the product pages:

List of articles AS-i total
Controllers / Gateways, network extension Power supplies and earth fault monitors Numberofinputs Numberofoutputs Inputvoltagefrom AS-i Outputvoltage acc.to PELV Max. inputcurrent /module [mA] Total outputcurrent / channel[A] AS-iprofileS - Total currentconsumptionfrom AS-i [mA] Draw-ing no. Orderno.
I/O modules for control cabinets 4 DI–yes–200–0.A.E<2501 AC2250 4 DI 4 DOT yes yes 200 1 (4) 7.0.E <250 1 AC2251
I/O modules for field applications

The current output of the power supplies is also stated on the productpages:

Safety at Work Outputcurrent 1[A] Outputvoltage 1AS-i [V] Outputcurrent 2[A] Outputvoltage 2[V] Outputvoltage 2AS-i [V] Nominal voltage[V] Draw-ing no. Orderno.
AS-i sensors, pneumatic and actuator solutions AS-i switched mode power supplies 428.5...31.6 DC4–28.5...31.6 DC115 / 230 AC4 AC1224 2.8 28.5...31.6 DC 6 24 DC – 115 / 230 AC 8 AC1209
Connection technology

Here is an example calculation to determine the suitable power supply: (25 modules 4I/4O, per module two inductive and two photoelectric sensors)I = (25 x 35 mA) + (25 x 4 x 5 mA) + (25 x 2 x 10 mA) + (25 x 2 x 35 mA)I

Accessories AS-i total AS-i total

= 3,625 mA x 1.10 = 3.987 A -> selected AS-i power supply: 4A. Or the rule of thumb is used: I

Technical information and customer service AS-i total

number of modules x 150 mA (e.g. 10 valves with 5 W each, 5 valves with 3 W each, 10 lamps with 45 mAeach)I 24 V power supply to supply the actuators Sum of the load currents (actuators): The actuators are supplied via a separate 24 V power supply with current (black auxiliary power cable). To calculate the required power supply rating simply add the current consumption values of the actuators:

24 V total

= 10 x 5 W / 24 V + 5 x 3 W / 24 V + 10 x 0.045 A = 3.16 A -> selected 24 V power supply: 4A. Visit our website: www.ifm-electronic.com

Bus system AS-Interface 2008/2009 - 544 19