Continuous Frequency Measurement - Siemens SIMATIC ET 200S Operating Instructions Manual

1Count5V
3.7 Measurement Modes
3.7.4

Continuous Frequency Measurement

Definition
In frequency measurement mode, the 1Count5V counts the pulses that arrive within a
dynamic measuring period.
Update Time
The 1Count5V updates the measured values cyclically. You preset the update time with the
Update Time parameter (see table). You can change the update time during operation.
Table 3- 11 Calculation of the Update Time
Boundary conditions
Non-isochronous mode
Isochronous mode
Any digits after the decimal point resulting from division by T
1
These limits may not be violated. If these limits are violated, the 1Count5V generates a parameter assignment error and
will not go into isochronous mode.
Frequency measurement
The value of the calculated frequency is made available in the unit 10
frequency value can be read in the feedback interface (byte 0 to 3).
Figure 3-25
172
Update time
Any T n x 10 ms
DP
T < 10 ms n x T
DP
T ≥ 10 ms n x T
DP
Frequency Measurement with Gate Function
Range of n
n
min
1
(10 ms/T [ms]) +1
DP DP
1
DP
are omitted.
DP
Operating Instructions, 06/2010, A5E00124867-07
n
max
1000
1000
1
10000 ms/T [ms]
DP
Hz. The measured
-3
Technological Functions
1