Rotational Speed Measurement With Integration Time - Siemens SIMATIC ET 200S Operating Instructions Manual

2.7.5

Rotational speed measurement with integration time

Definition
In rotational speed measurement mode, the 1Count24V counts the pulses that arrive from a
tachometer generator within a set integration time and calculates the speed of the connected
motor.
Integration Time
You preset the integration time with the Integration Time parameter (see table).
Table 2- 11 Calculation of the Integration Time
Boundary conditions
Non-isochronous mode
Isochronous 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 1Count24V generates a parameter assignment error and
will not go into isochronous 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 2-25
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
Integration 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
1Count24V
2.7 Measurement Modes
n
max
1000
1000
1
10000 ms/T [ms]
DP
1
63