Can you tell me,please, where (or how?) in simatic s7, siemens, 300, can i find a 1Hz freq for use as 1 second puls for trigering counters (some kind of counting hours with two retentive counters)...
Hardware Configuration > CPU Properties > Clock Byte
Check the box and identify the byte you wish to have used as the clock byte. Each bit in this byte will then be pulsed by the CPU's operating system at a different fixed time interval. Check the online help to find more information about which bit you require.