FAQ
How are Velocity and acceleration scaled?
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How are Velocity and Accceleration scaled?
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The register V_SOLL(5) and A_SOLL(6) are scaled values.
Normally the Velocity values are like this for incremental encoders:
And for the accelerations they are like this:
But since the Encoder resolution and the Sample Frequency is also a part of the equation we have these formulers for the calculation of the right values:
Velocity:
RPM = (V_SOLL/16) * Sample Frequency / Encoder resolution ) * 60
Acceleration:
RPM/s = ( A_SOLL/16) * ( Sample Frequency^2 / Encoder Resolution ) * 60
The standard Sample Frequency for MAC050-141 is always 520,8 Hz ( 1.92 ms ).
For MAC400-4500 it's 769,23 Hz ( 1.3 ms ) or 384,60 Hz ( 2.6 ms ).
But when we use Ethernet ( EtherCAT and Sercos ) it can also be either 1kHz ( 1 ms ) or 500Hz ( 2 ms ) synchronized and also for Ethernet/IP and PowerLink under some circumstances.
The Actual Velocity is using another equation:
RPM = V_IST * sample Frequency / Encoder resolution * 60
For MAC050-141 this means that 100 units = 763 RPM.
But the result of this is also that the accuracy of what you read is +/-8RPM. |
JVL A/S Bregnerødvej 127 DK-3460 Birkerød Denmark
Tel: +45 4582 4440 Fax: +45 4582 5550 E-mail: jvl@jvl.dk
Tel: +45 4582 4440 Fax: +45 4582 5550 E-mail: jvl@jvl.dk
