IO-Link Parameterization
2
0
2
0
-0
9
31
6.10
Config - Position Overflow
Configuration - Position Overflow
The "Config - Position Overflow" parameter is used to set the highest position value for the cur-
rent measured position value.
As soon as the "Position Overflow" value is exceeded, the position value reverts to "0" and con-
tinues counting up from there. Conversely, as soon as the position value falls below "0," the
measured value jumps to the "Position Overflow" value and continues counting down from
there. This is used for cyclical applications with a consistent direction of rotation (e.g., winding
paper rolls).
The figure below illustrates this.
Figure 6.13
Switching point characteristics with overflow function
The maximum permissible multiturn position of the encoder is set using the "Config - Position
Overflow" setting. This parameter can therefore also be considered as a total resolution in addi-
tion to "Config - ST Resolution." The figure above shows that two full revolutions are possible.
The third revolution is counted upward by a further 1/4. Once the overflow value has been
exceeded, the position value begins counting again from zero.
A Mathematical Generalization for this Relationship
•
Singleturn resolution = Config - ST Resolution = number of measuring steps per revolu-
tion
•
Maximum possible multiturn position = maximum number of possible full revolutions
(Config - Position Overflow) / (Config - ST Resolution)
—
?round off the result = (maximum possible multiturn position)
In addition:
"Config - Position Overflow" must always be greater than or equal to "Config - ST Resolution"
Taking the sample numbers from the illustration above, the result is:
•
Singleturn resolution = Config - ST Resolution = MDC1 Resolution = number of measur-
ing steps per revolution = 1000
Index
Sub
Parameter
Access
Data Type
Length
100 (0x64)
Config - Position Overflow
rw
Integer
32 bits
Overflow
=
2250
0
shaft
0
shaft
1000
shaft
2000
shaft
Index
Parameter
Value
0x64
Config-Position Overflow
2250
0x60
Config-STR Resolution
1000
Shaft position
exceeds Overflow
Start first application cycle
Start next application cycle
first encoder
revolution
second encoder
revolution
partial
revolution