Technical Manual
WDGA with EtherNet/IP
3 - Device description
© Wachendorff Automation GmbH & Co. KG
10
The scaling parameter "Total measuring range in measuring units (TMR)"
— the
maximum total measuring range of the position value (singleturn and multiturn
multiplied)
— indicates the total resolution of the encoder. When the position value
reaches TMR -1, it jumps back to 0 and vice versa.
As a rule, the selected TMR parameter should be an integer multiple of the "Measuring
units per revolution (MUPR)" (see equation (4)), so that the zero point is always at the
same position of the encoder shaft.
𝑇𝑀𝑅 = 36000 𝐶𝑡𝑠
(3)
𝑀𝑇 =
𝑇𝑀𝑅
𝑀𝑈𝑃𝑅
=
36000 𝐶𝑡𝑠
3600 𝐶𝑡𝑠
= 10
(4)
In exceptional cases, it is suitable that TMR is not an integer multiple of MUPR
— for
example, in a system in which a gear ratio ensures that the desired measured variable
is moving 10% faster relative to the encoder shaft.
In this case, a setting of MUPR = 3960 Cts and TMR = 36000 Cts would ensure that
the faster (but not directly measurable) shaft can be measured with a resolution of 0.1°
and over a range of 10 revolutions. Normally, the number of revolutions would be
calculated by dividing the position value by MUPR. In this case, however, it must be
divided by 3600 Cts, since the result would otherwise be the number of revolutions of
the encoder shaft and not the faster shaft of the system.
•
It should be noted that measurement errors will occur if the
result of this formula is a decimal.