Contact assignment and LED displays

KL2521-xxxx - Contact assignment

KL2521-xxxx - LED displays

Connecting the inputs (KL2521-0000, KL2521-0024)

The optically isolated inputs are protected from overload by a current limiter. Without further external circuitry the operating voltage may lies between 5 V and 24 V_DC. The GND connection is the common ground for the two inputs, T and Z. The circuit diagram shows the internal circuitry of the two inputs:

Connection of the outputs

Circuit examples for output to A. The same principles apply to output B.

KL2521-0000, KL2521-0010

The outputs A and B of the EL2521 can be used in different connection modes. An integrated DC/DC converter supplies the output stage of the two channels, A and B, with an electrically isolated 5 V power supply.

• Connection to RS485/RS232 receiver
  The output can be operated as RS485 or as RS232 output. The circuit generates the necessary differential signals.

• Connection to optocoupler (without external supply voltage)
  The outputs can be used for direct connection of an optocoupler. The output stage supplies the necessary output current using an internal 5 V supply voltage.

Connection to optocoupler (with external supply voltage)

For connection to inputs with a large input resistance, an external supply voltage (up to 24 V) can be used with the EL2521-0024 in order to create the necessary current.

Operation with an external supply voltage is dependent on the hardware version The operation with an external supply voltage depends on the hardware version of the terminal: You can use the standard variant KL2521-0000 for this up to hardware version 03. From hardware version 04 this is only possible with the special variant KL2521-0024, which was specially optimized for this application! However, since the KL2521-0024 has no internal supply voltage (5 V) it is not suitable for connection to RS485/RS232 receivers or optocouplers without an external supply voltage.

• KL2521-0000 up to hardware version 03



• Instead of hardware version 04 (or higher), use the special variant KL2521-0024

See chapter Documentation issue status for the determination of the hardware version

KL2521-0024: Connection to external electronics

Note when connecting external electronics that terminal point A of the first channel and terminal point B of the second channel of a KL2521-0024 are connected to each other internally.

This allows the dual-channel connection of external electronics if the KL2521-0024 switches the ground of the connected device as shown in example 1.

Notes on connection to external electronics The Beckhoff KL5111, KL5121, KL5151 and KL5152 incremental encoder interface terminals require the switching of the positive voltage. Because the terminal points A and B of the KL2521-0024 are bridged internally, the KL2521-0024 cannot switch the two inputs of the KL5151-0000 shown in example 2 independently of each other. This circuit crossed out in red is therefore of no use! As shown in example 3, however, you can use one channel of the KL2521-0024 to switch one channel of the KL5151-0000.

KL2521-0010 Connection of additional outputs T, Z

The outputs are realized by MOSFET switches and can switch AC and DC voltages up to 230 V. The maximum current is 100 mA. DC voltages can be switched positive and negative.

Ausgang T, Z

Wiring