BECKHOFF KL2521-0000 - Manual (Page 10)

Functional description
8 KL2521
Connection to an optocoupler (with external power supply)
For connection to inputs with large internal impedances, an external power
supply (of up to 24 V) can be used in order to create the necessary current.
i
Note
The operation with external power supply depends on the hardware
version of the terminal:
• until hardware version 03 you can use the standard terminal
KL2521-0000 for this.
• from hardware version 04 this is only possible with special terminal
KL2521-0024, that is especially optimized for this application!
But because the KL2521-0024 misses the internal power supply
(5 V), it is not suitable for connection of a RS232/485 receiver or
an optocoupler without external power supply.
Check the hardware
version The firmware and hardware version (delivery state) can be found in the
serial number printed at the side of the terminal.
Structure of the serial number:
WW YY FF HH
WW - week of production (CW, calendar week)
YY - year of production
FF - firmware version
HH - hardware version
Example with ser. no.: 12 06 4F 03:
12 - week of production 12
06 - year of production 2006
4F - firmware version 4F
03 - hardware version 03
Until hardware version 03
7...24V
KL2521-0000
4K7
+A
- A
Instead of hardware version 04 (or higher) use special terminal
KL2521-0024
4K7
KL2521-0024
+A
- A
7...24V