Siemens Simatic series Manual page 27

Parameters/address space
4.2 Address space
Control interface
The figure below shows the address assignment of the module in the process image output.
You use the control interface, for example, to start the counter or to set the counter value.
With the "SW gate" control bit you open and close the software gate of the corresponding
channel.
Figure 4-5
26
Assignment of the address space of the control interface of the DI 16x24VDC Count
(bytes 0 to 7)
DI 16x24VDC HF Digital Input Module (6ES7521-1BH00-0AB0)
Manual, 08/2018, A5E03485952-AG