Counter Statuses And Signal Flow In The Three Function Modes; The Normal Counter Function - Siemens SIMATIC S5 Manual

The Counter Functions
4.3

Counter Statuses and Signal Flow in the Three Function Modes

The interplay of the individual signals and the sequence of a count process are essential to an
understanding of the functions. For this reason the signal sequence is described briefly in the
following two subsections.
4.3.1

The Normal Counter Function

The normal counter function is a 16-bit up counter which works without setpoints and has no direct
access to the IP output.
The following example should make the signal sequence clear.
Before the start of the function, the counter was set to the PCF function on both channels.
The output of channel 1 was set.
8 7 6 0 1
CS1
CU1
GATE1
Q1
RSQ1
CF1
CASC
RSC1
Reset pulse for counter (asynchronouus to
counter pulse)
Time of function selection
"Normal counter function" is selected for channel 1 with CF1 = 1 .
The rising edge of the RSC1 signal sets the counter to the start value "0" for NCF
Output A is switched off when you switch to the normal counter function. This output is not set in
the normal counter function.
Reset signals via input RSQ remain without effect for this reason.
The GATE signal is transparent throughout, i.e. the reset signals for the counter can still be
switched even when the GATE signals are active.
However, pending counter pulses do not change the current counter status.
4-4
2 3 0 1 2
Figure 4-1. Pulse Diagram for Channel 1
Standard Function Counter
0
65535
. . . .
Counter
overflow
1 2 2 0 0 1 2 3
Reset counter 1
Counter status
CS1 =
EWA 4NEB 812 6131-02
1
0
1
0
1
0
1
0
1