Examples Of Counting - Siemens Simatic series Manual

Parameters/address space
4.2 Address space
4.2.3

Examples of counting

In this section, you will find examples of the behavior of the counter and how you can specify
this behavior. You specify the properties of the counter in the parameter assignment.
Behavior when a counting limit is exceeded - Stop counting
The following section describes the effects of the parameter "Behavior when a counting limit
is exceeded = Stop counting". To control the counter, the bits of the control byte of the
control interface are used, see section Address space Counting mode (Page 25)
Counting begins at the current counted value (the SW_GATE is set in the control byte). Bit
sequence in the control byte of the control interface 0000 1000.
After the high counting limit is violated, counting is aborted (counting stops) and the counted
value jumps to the low counting limit = 0. The STS_GATE bit is reset.
To restart the counting, the SW_GATE bit must be reset via the control interface and set
again.
Whether or not counting is started again with the current counter value or with the start value
depends on the command byte in the control interface.
Bit sequence in control byte of the control interface:
● bit 0 to 2 = "000" Start with current counter value
● bit 0 to 2 = "010" Start with start value
If the SW_GATE bit is reset in the control byte of the control interface before reaching the
high counting limit, counting is stopped.
The following figure shows an example of the principle of stopping counting when a counting
limit is exceeded.
Figure 4-9
30
Principle: Stop counting
DI 16x24VDC HF Digital Input Module (6ES7521-1BH00-0AB0)
Manual, 08/2018, A5E03485952-AG