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

2.7.8

Continuous Period Measurement

Definition
In period measurement mode, the 1Count24V indicates the dynamic measuring time as a
period. If the period is less than the update time, then an average is calculated for the period.
Update Time
The 1Count24V 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 2- 16 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 1Count24V generates a parameter assignment error and
will not go into isochronous mode.
Period measurement
The value of the calculated period is given in the unit 1 µs or 1/16 µs. The measured period
can be read in the feedback interface (byte 0 to 3).
Figure 2-28
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
Update time
Any T n x 10 ms
DP
T < 10 ms n x T
DP
T ≥ 10 ms n x T
DP
Period Measurement with Gate Function
Range of n
n
min
1
10 ms/T [ms] +1
DP DP
1
DP
are omitted.
DP
1Count24V
2.7 Measurement Modes
n
max
12000
12000
1
120000 ms/T [ms]
DP
1
69