KL2502, KL2512 - Dual Channel Pulse Width Output Terminals, 24 V DC

Basic Function Principles


The KL2502 output terminal modulates the pulse width of a binary signal. The peripheral side of the electronics is electrically isolated from the internal K-bus, and therefore also from the fieldbus. The cycle (base frequency) and the pulse/pause ratio are configurable. 16-bit values can be specified for setting purposes via the process image of the controller.

In the delivery state the KL2502 terminal occupies 6 bytes in the process image. The mapping of the KL2502 can be set by means of the controller or by the Bus Coupler's configuration interface using the Beckhoff KS2000 configuration software.

In addition to PWM mode, the KL2502 can also be operated in FM mode (frequency modulation), or with pulse direction setting for stepper motor control (Frq-Cnt pulse mode).

The default setting of the terminal in delivery state is PWM mode with a base frequency of 250 Hz and a resolution of 10 bit.


The LEDs indicate the operating state of the associated terminal channels.

green Run LED:
On: normal operation
Off: Watchdog timer overflow has occurred. If no process data are transmitted by the Bus Coupler for 100 ms, the green LEDs go out. The output assumes a user-specified voltage (see Feature register).

Process data

Input format:

KL2502: Two's complement representation (integer -1 corresponds to 0xFFFF)
The ratio of duty cycle/period is specified with a maximum resolution of 10 bit.

KL2512: 16 bit unsigned integer

Output value
Process data
0 % Duty Cycle
0x0000 (0dec)
0x7FFF (32767dec)
0xFFFF (65535dec)
50 % Duty Cycle
0x3FFF (16383dec)
0x3FFF (16383dec)
0xBFFF (49151dec)
100 % Duty Cycle
0x7FFF (32767dec)
0x0000 (0dec)
0x8000 (32768dec)

*) The KL2512 passes through the output values (0…100 % duty cycle) twice.