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 always have 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

The assignment of the other terminals:

Terminals	Signal	Description
1.0 to 1.7	unused
2.0 and 3.0	I0 and I1	Input signals for the digital inputs I0 and I1
4.0	N01	Neutral conductor for the digital inputs I0 and I1
2.1 and 3.1	I2 and I3	Input signals for the digital inputs I2 and I3
4.1	N23	Neutral conductor for the digital inputs I2 and I3
2.2 and 3.2	I4 and I5	Input signals for the digital inputs I4 and I5
4.2	N45	Neutral conductor for the digital inputs I4 and I5
2.3 and 3.3	I6 and I7	Input signals for the digital inputs I6 and I7
4.3	N67	Neutral conductor for the digital inputs I6 and I7
2.4	R0	Common contact of the first relay output
3.4 and 4.4	NO0 and NC0	NO and NC contacts of the first relay output
2.5	R1	Common contact of the second relay output
3.5 and 4.5	NO1 and NC1	NO and NC contacts of the second relay output
2.6	R2	Common contact of the third relay output
3.6 and 4.6	NO2 and NC2	NO and NC contacts of the third relay output
2.7	R3	Common contact of the fourth relay output
3.7 and 4.7	NO3 and NC3	NO and NC contacts of the fourth 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 DX531. 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 following figure shows the electrical connection of the module:

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 4 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.
• All input signals must come from the same phase of the same supply system (together with the used neutral conductor). The module is designed for 120/230 VAC max., not for 400 VAC, not even between two input terminals.
• All neutral conductor connections must be common to the same supply system, since the terminals 4.0 to 4.3 are interconnected within the module. Otherwise, accidental energization could occur.

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.

The module provides several diagnosis functions (see chapter Diagnosis and State LEDs DX531 - Digital Input/Output Module).