Using the SSI_Absolute_Encoder technology object
4.4 Configuring SSI_Absolute_Encoder
Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG
151
Specify measured value (SSI_Absolute_Encoder)
Measured variable
With this parameter you specify whether the technology module is to provide a certain
measured variable (Page 59) or the complete SSI frame.
You can select from the following options:
Additional option-specific pa-
rameters
Frequency
(default)
The measured variable shows the number of increments per
second, where each increment corresponds to one position
value change. The value is a floating point number (REAL). The
unit is Hz.
The technology object displays the measured value at the output
parameter MeasuredValue.
• Update time
Period The measured variable is the average period between two in-
crements of the position value. The value is an integer (DINT).
The unit is s.
The technology object displays the measured value at the output
parameter MeasuredValue.
• Update time
Velocity The measured variable is a velocity.
Examples of a velocity measurement can be found in the expla-
nation of the "Increments per unit" parameter.
The technology object displays the measured value at the output
parameter MeasuredValue.
• Update time
• Time base for velocity meas-
urement
• Increments per unit
Complete SSI frame Instead of a measured variable, the first 32 bits of the SSI frame
are returned (bit 0 to bit 31). In so doing, special bits that do not
belong to the position information are also supplied. A config-
ured inversion of the direction is ignored.
The technology object displays the value at the output parame-
ter CompleteSSIFrame.
You can find examples under Examples of the frame format
(Page 153). This option is only available in operating mode "Use
position value (SSI absolute value) as reference".
—
Note
If the increment per revolution is required for calculation of the measured values, it is
automatically calculated from the parameterized telegram length as the power of 2, e.g. 8192
increments per revolution with a
telegram length of 13 bit. If you are using an SSI absolute
encoder whose increment per revolution does not correspond to the power of 2, the
calculated measured value may be incorrect for a short time.
To Next Page
Loading...
