Connecting the power supply

Notice

Damage to the Embedded PCs

The Embedded PCs may be damaged during wiring.

The cables for the power supply should only be connected in de-energized state.

The power supply terminals require an external voltage source, which provides 24 V DC (-15% / +20%). The power supply terminal must provide 4 A at 24 V, in order to ensure the operation of the Embedded PCs in all situations.

The cabling of the Embedded PC in the control cabinet must be done in accordance with the standard EN 60204-1:2006 PELV = Protective Extra Low Voltage:

The "PE" and "0 V" conductors of the voltage source for a basic CPU module must be on the same potential (connected in the control cabinet).
Standard EN 60204-1:2006, section 6.4.1:b stipulates that one side of the circuit, or a point of the energy source for this circuit must be connected to the protective earth conductor system.

Connection example

Legend for the connection example
No.	Description
1	The upper spring-loaded terminals identified with “24 V“ and “0 V“ supply the Embedded PC and the Terminal Bus (data transfer via K- or E-bus).
2	The spring-loaded terminals identified as "+", "-" and "PE" supply the Bus Terminals via the power contacts and the sensors or actuators connected to the Bus Terminals.

The cables of an external voltage source are connected to the power supply unit with spring-loaded terminals.

Required wire cross-sections and strip lengths.
Conductor cross-section	0,5 ... 2,5 mm²	AWG 20 ... AWG 14
Strip length	8 ... 9 mm	0.33 inch

The voltage source has been connected to the power supply unit successfully when the two upper power supply terminal LEDs light up in green.
The left LED (Us) indicates the supply of the basic CPU module and terminal bus. The right LED (Up 24V) indicates the Bus Terminal supply via the power contacts.

Notice

Interrupting / switching off the power supply

To switch off the Embedded PC, do not disconnect the ground (0 V), because otherwise current may continue to flow via the shielding, depending on the device, and damage the Embedded PC or peripheral devices.

Always disconnect the 24 V line. Devices connected to the Embedded PC, which have their own power supply (e.g. a Panel) must have the same potential for "PE" and "0 V" as the Embedded PC have (no potential difference).

Observe the UL requirements

The CX9020 Embedded PCs are UL certified. The corresponding UL label can be found on the type plate.

Connecting the power supply 4: — UL label for CX9020 Embedded PC.

The CX9020 Embedded PCs can thus be used in areas in which special UL requirements have to be met. These requirements apply to the system voltage (Us) and to the power contacts (Up). Application areas without special UL requirements are not affected by UL regulations.

UL requirements

The Embedded PCs must not be connected to unlimited voltage sources.
Embedded PCs may only be supplied from a 24 V DC voltage source. The voltage source must be insulated and protected with a fuse of maximum 4 A (corresponding to UL248).
Or the power supply must originate from a voltage source that corresponds to NEC class 2. An NEC class 2 voltage source must not be connected in series or parallel with another NEC class 2 voltage source.