Electrical \ Connection

The input/output modules are plugged on I/O Terminal Units TU515 or TU516 I/O Terminal Units TU515 and TU516 for I/O Expansion Modules. Properly seat the modules and press until they lock in place. The Terminal Units are mounted on a DIN rail or with 2 screws plus the additional accessory for wall mounting (TA526 Wall Mounting Accessory TA526).

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.

Note

Mounting, disassembling and electrical connection for the Terminal Units and the I/O modules are described in detail in S500 System Data S500 System Data, Overview.

The terminals 1.8, 2.8, 3.8 and 4.8 as well as 1.9, 2.9,3.9 and 4.9 are electrically interconnected within the I/O Terminal Units and have always the same assignment, independent of the inserted module:

Terminals 1.8, 2.8, 3.8 and 4.8: Process voltage UP = +24 V DC

Terminals 1.9, 2.9, 3.9 and 4.9: Process voltage ZP = 0 V

The assignment of the other terminals:

Terminals Signal Meaning
1.0 to 1.7 I0- to I7- Minus poles of the 8 analog inputs
2.0 to 2.7 I0+ to I7+ Plus poles of the 8 analog inputs
3.0 to 3.7 O0- to O7- Minus poles of the 8 analog outputs
4.0 to 4.7 O0+ to O7+ Plus poles of the 8 analog outputs

Caution

The minus poles of the analog inputs are electrically connected to each other. They form an “Analog Ground” signal for the module. The minus poles of the analog outputs are also electrically connected to each other to form an “Analog Ground” signal.

Caution

There is no electrical isolation between the analog circuitry and ZP/UP. Therefore, the analog sensors must be electrically isolated in order to avoid loops via the earth potential or the supply voltage.

Caution

Because of their common reference potential, analog current inputs cannot be circuited in series, neither within the module nor with channels of other modules.

Note

For the open-circuit detection (cut wire), each channel is pulled up to “plus” by a high-resistance resistor. If nothing is connected, the maximum voltage will be read in then.

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 V DC power supply at the terminals L+/UP and M/ZP of the CPU/Bus Module increases by 2 mA per AX522.

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

Caution

:strong:Risk of damaging the PLC modules!

The PLC modules can be damaged by overvoltages and short circuits.

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

Note

Generally, analog signals must be laid in shielded cables. The cable shields must be earthed at both sides of the cables. In order to avoid unacceptable potential differences between different parts of the installation, low resistance equipotential bonding conductors must be laid.

Only for simple applications (low disturbances, no high requirement on precision), the shielding can also be omitted.

The following figure shows the electrical connection of the analog input/output module AX522:

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Terminal assignment of AX522

The modules provide several diagnosis functions Analog Input/Output Module AX522 Analog Input/Output Module AX522.