Eliminated from:
Library LenzeElectricalShaft V01.03.04.00 and higher, included from Engineer HighLevel 2.10 SP2 onwards
Behaviour of the new version?
In the new version, values not equal to a power of two 2^n can also be entered in code C5273 for the resolution of an encoder revolution without there being any incorrect calculation at the
dnPosOut_p position output.
What happens?
The
dnPosOut_p position output at the
L_EsEncoderConv function block indicates values that do not correspond to the encoder value (raw position at the
dnEncoderIn input).
When does the problem occur?
This behaviour is caused by the setting in code C5273 for the resolution of an encoder revolution. If this value has been set as not equal to a power of two 2^n, the next lower power of two 2^n is incorrectly used for calculating inside the function block.
Possibilities of diagnosis?
The
dnPosOut_p position output at the
L_EsEncoderConv function block indicates values that do not correspond to the encoder value (raw position at the
dnEncoderIn input).
Short-term measures/recommendations?
If encoders with a resolution per revolution not equal to a power of two 2^n are used, a scaling block can be connected upstream of the
L_EsEncoderConv function block. This scaling block
L_TbMulDivLim re-scales the raw encoder position (the function block interconnection is shown in the diagram below).
- The numerator (L_TbMulDivLim.dnNumerator) must be a power of 2 and must correspond to the value of code C5273 set in the L_EsEncoderConv function block.
- The denominator (L_TbMulDivLim.dnDenominator) must be the value of the real resolution of an encoder revolution.
Evaluation:
The functional restriction typically concerns applications in which position values of an external absolute rotary encoder are routed to the application via a data bus. In this case, the
L_EsEncoderConv function block is converted into the existing axis system or external measuring system for mapping purposes..
Because most existing encoder systems divide an encoder revolution into 2^n steps (value of a power of two), the functional restriction has no effect here. In the case of all other resolutions, the procedure described under
Short-term measures/recommendations can be used to remedy the situation.
