Technical data

Table Of Contents
SFBs for Compact CPUs
System Software for S7-300/400 System and Standard Functions - Volume 2/2
28-32
A5E00739858-01
28.4 Controlling the Frequency Measurement with SFB 48
"FREQUENC"
Description
You can operate the frequency counter via user program. In this case you must
use SFB FREQUENC (SFB48).
The following operations are available:
Starting/stopping the via software gate SW_GATE
Enabling/controlling the output DO
Retrieving the status bits STS_CMP, STS_OFLW and STS_UFLW
Retrieving the actual frequency value MEAS_VAL
Jobs for reading/writing the internal frequency counter registers
Parameter
Parameter Declaration Data
type
Address
(Instance
DB)
Range of values Default Description
LADDR
INPUT WORD 0 CPU specific W#16#0300 The I/O
address of
your
submodule,
specified by
you in "HW
Config".
If the I and O
addresses
are not equal,
the lower one
of the two
must be
specified.
CHANNEL
INPUT INT 2
CPU 312C:
0 to 1
CPU 313C:
0 to 2
CPU 314C:
0 to 3
0 Channel
number:
SW_GATE
INPUT BOOL 4.0 TRUE/FALSE FALSE Software gate
for starting/
stopping the
frequency
measurement
MAN_DO
INPUT BOOL 4.1 TRUE/FALSE FALSE Enable
manual
output control
SET_DO
INPUT BOOL 4.2 TRUE/FALSE FALSE Control
output