SBC PCD1 Series Manual page 246

Saia-Burgess Controls AG
Block diagram
Input
Interface
Output
Interface
Operating principle
This can be largely derived from the block diagram. It is only necessary to add some
explanation about the counter output circuit:
The output of the internal counter is identified as "Counter Flag". The user has no
hardware access to it. This counter flag is set to "1" whenever the counter is loaded
or by means of a separate instruction.
The flag is set to "0" in up-counting mode:
To reset a CCO hardware output which had previously been set high by the user
program, it is necessary to differentiate between two cases:
a) count range between 0 ... 6 5,535 (normal case)
b) count range exceeding 65,535
Case a):
Counter Flag
Reset Enable
CCO
The "Reset-Enable" should be activated before the counter reaches zero.
Manual Manual PCD 1 / PCD 2 Series │ D ocument 26 / 737 EN22 │ 2 013-11-26
Counter enable
Clock
Input
filters
Inputs
A
in down-counting mode:
Resetting the counter flag results in a simultaneous reset of the CCO
output.
0
Counter Flag
Set
Counter
Set CCO Set CCO
Counter Status Flag
up/down
Counter Mode
SC x1 x2 Mode
B
when counter value 65,535 is
reached
when counter value 0 is reached
50'000
Input/output (I/O) modules
Fast counting modules
U+
CCO
5
5-110