Siemens SIMATIC ET 200SP - Page 153

Using the SSI_Absolute_Encoder technology object
4.4 Configuring SSI_Absolute_Encoder
Counting, measurement and position detection
152 Function Manual, 12/2017, A5E32009889-AG
Update time
By configuring the update time (Page 59) in milliseconds, you can specify the time interval
between two measured value updates. Unsteady measured variables can be smoothed
through longer update times
If you enter "0", the measured value is updated once per module-internal cycle. Up to three
decimal places can be entered. A value from 0.0 to 25000.0 is permissible. The default
setting is "10.0".
Time base for velocity measurement
This parameter defines the time base on which the velocity is to be returned.
You can select from the following options:
● 1 ms
● 10 ms
● 100 ms
● 1 s
● 60 s/1 min
The default setting is "60 s/1 min".
Increments per unit
With this parameter you define the number of increments per relevant unit that the SSI
absolute encoder supplies for the velocity measurement.
You can enter a value between 1 and 65535.
Example 1:
Your absolute encoder operates with a resolution of 12 bits per revolution and performs 4096
increments per revolution. The velocity should be measured in revolutions per minute.
In this case, you need to assign the following parameters:
● Increments per unit: 4096
● Time base for velocity measurement: 60 s/1 min
Example 2:
You encoder delivers 10000 increments for travel over one meter. The velocity is to be
measured in meters per second.
In this case, you need to assign the following parameters:
● Increments per unit: 10000
● Time base for velocity measurement: 1 s