Electrical Connection

The electrical connection of the I/O channels is carried out using the 40 terminals of the I/O terminal unit. I/O modules can be replaced without re-wiring the terminal units.

The terminals 1.8 to 4.8 and 1.9 to 4.9 are electrically interconnected within the I/O terminal unit and have always the same assignment, irrespective of the inserted module:

• Terminals 1.8 to 4.8: process voltage UP = +24 VDC
• Terminals 1.9 to 4.9: process voltage ZP = 0 V

Assignment of the other terminals:

Terminals	Signal	Description
1.0 to 1.7	I0 to I7	Input signals of the 8 digital inputs
1.8 to 4.8	UP	Process voltage +24 VDC
1.9 to 4.9	ZP	Reference potential for the 8 digital inputs and the process voltage
2.0	R0	Common contact of the first relay output
3.0	NO 0	Normally-open contact of the first relay output
4.0	NC 0	Normally-closed contact of the first relay output
2.1	R1	Common contact of the second relay output
3.1	NO 1	Normally-open contact of the second relay output
4.1	NC 1	Normally-closed contact of the second relay output
:	:	:
2.7	R7	Common contact of the eighth relay output
3.7	NO 7	Normally-open contact of the eighth relay output
4.7	NC 7	Normally-closed contact of the eighth relay output

The internal power supply voltage for the module’s circuitry is carried out via the I/O bus (provided by a bus module or a CPU). Thus, the current consumption from 24 VDC power supply at the terminals L+/UP and M/ZP of the CPU/bus module increases by 2 mA per DX522.

The external power supply connection is carried out via the UP (+24 VDC) and the ZP (0 VDC) terminals.

Attention

:strong:Risk of damaging the PLC modules!

Overvoltages and short circuits might damage the PLC modules.

• Make sure that all voltage sources (supply and process voltage) are switched off before you begin with operations at the system.
• Never connect any voltages or signals to reserved terminals (marked with —). Reserved terminals may carry internal voltages.

Warning

:strong:Risk of death by electric shock!

The terminals of the module can carry 240 V voltage.

Make sure that all voltage sources (supply and process voltage) are switched off before you begin with operations at the system.

The module provides several diagnosis functions (see Diagnosis and State LEDs DX522 - Digital Input/Output Module).

The following figure shows the electrical connection of the digital input/output module DX522.

Electrical connection of the digital input/output module DX522

Attention

:strong:Risk of damaging the PLC module!

The following things have to be considered when connecting input and output voltages to the module:

• All 230 VAC feeds must be single-phase from the same supply system.
• Connection of 2 or more relay contacts in series is possible; however, voltages above 230 VAC and 3-phase loads are not allowed.
• The 8 switch-over contacts of the relays are electrically isolated from channel to channel. This allows to connect loads of 24 VDC and 230 VAC to relay outputs of the same module. In such cases it is necessary that both supply voltages are grounded to prevent unsafe floating grounds.

Attention

:strong:Risk of damaging the PLC module!

There is no internal short-circuit or overload protection for the relay outputs.

Protect the relay contacts by back-up fuses of 6 A max. (characteristic gG/gL). Depending on the application, fuses can be used for single channels or module-wise.