Continuous Rotational Speed Measurement - Siemens SIMATIC ET 200S Operating Instructions Manual

1Count5V/500kHz
3.7 Measurement Modes
3.7.6

Continuous Rotational Speed Measurement

Definition
In rotational speed measurement mode, the 1Count5V/500kHz counts the pulses that are
received from a tachometer generator within a dynamic measuring time, and calculates the
speed from this value with the number of pulses per encoder revolution.
Update Time
The 1Count5V/500kHz 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 3-14 Calculation of the Integration Time
Boundary conditions
Non-isochrone mode
Isochrone mode
Any digits after the decimal point that come about after dividing by T
1
These limits must not be violated. If these limits are violated, the 1Count5V/500kHz generates a parameter assignment
error and will not go into isochrone mode.
Rotational Speed Measurement
For rotational speed measurement mode, you also have to assign the pulses per encoder or
motor revolution.
The rotational speed is returned in the unit 1x10
Figure 3-27
174
Update time
Any T n x 10 ms
DP
T < 10 ms n x T
DP
T ≥ 10 ms n x T
DP
Rotational Speed Measurement with Gate Function
Range of n
n
min
1
(10 ms/T [ms]) +1
DP DP
1
DP
are omitted.
DP
/min.
-3
Operating Instructions, 02/2007, A5E00124867-05
n
max
1000
1000
1
ms/T [ms]
DP
Technological Functions
1