VIPA CPU 312SC - SFB 48 - FREQUENC - Frequency Measurement

n Basic parameters
Here the interrupts, the counter component should trigger, may be
selected. You have the following options:
–
None: There is no interrupt triggered.
– Process: The counter component triggers a hardware inter-
rupt.
– Diagnostics and Process: With the CPU the diagnostic inter-
rupt of the digital in-/output periphery is only supported in con-
nection with "hardware interrupt lost".
n Frequency measurement
The following parameters are relevant for frequency measure-
ment. Parameters, which are not listed here, are ignored by the
CPU.
– Integration time:
Integration time for frequency measurement
Range of values: 10 ... 10000ms
– Hardware interrupt:
End of measurement (End of integration time)
When activated, with each end of the integration time, a hard-
ware interrupt is triggered.
6.6.4 SFB 48 - FREQUENC - Frequency measurement
The SFB 48 is a specially developed block for the CPU 31xSC for fre-
quence measurement.
n The SFB FREQUENC should cyclically be called (e.g. OB 1) for
controlling the frequency measurement.
n The SFB is to be called with the corresponding instance DB. Here
the parameters of the SFB are stored.
n Among others the SFB 48 contains a request interface. Hereby
you get read and write access to the registers of the frequency
meter.
n So that a new job may be executed, the previous job must have
be finished with JOB_DONE = TRUE.
n Per channel you may call the SFB in each case with the same
instance DB, since the data necessary for the internal operational
are stored here. Writing accesses to outputs of the instance DB is
not permissible.
n With the SFB FREQUENC (SFB 48) you have following functional
options:
–
Start/Stop the frequency meter via software gate SW_GATE
– Read the status bit
– Read the evaluated frequency
– Request to read/write internal registers of the frequency meter.
Name Declaration Data type Address
(Inst.-DB)
Default
value
Comment
LADDR INPUT WORD 0.0 300h This parameter is not eval-
uated. Always the internal
I/O periphery is addressed.
CHANNEL INPUT INT 2.0 0 Channel number
Description
Parameters
VIPA System 300S Deployment I/O periphery
Frequency measurement > SFB 48 - FREQUENC - Frequency measurement
HB140 | CPU-SC | 312-5BE13 | GB | 15-50 123