Instruction Manual PSx3xxEC
29
4.6
Using actual value assessment factors to set the spindle pitch
SDO #2010 (numerator factor) and #2011 (denominator factor) can be used to
represent any desired spindle pitch:
number of steps per revolution = 400 *
𝑑𝑒𝑛𝑜𝑚. 𝑓𝑎𝑐𝑡𝑜𝑟
𝑛𝑢𝑚𝑒𝑟𝑎𝑡𝑜𝑟 𝑓𝑎𝑐𝑡𝑜𝑟
Both factors are set to a value of 400 by default, resulting in a resolution of 0.01 mm
at a spindle pitch of 4 mm.
The denominator factor serves as a simple means of setting the spindle pitch and
resolution.
The numerator factor is primarily used for se
tting “unlevel” resolutions.
Examples:
Spindle pitch
Resolution
Numerator
factor
Denominator
factor
4 mm
1/100 mm
400
400
1 mm
1/100 mm
400
100
2 mm
1/10 mm
400
20
Numerator and denominator factors may take on values between 1 and 10,000.
4.7
Drag error monitoring
During a positioning run, the device compares the computed target position with the
current actual value. If the
difference is larger than the ‘drag error’ value (SDO
#2005), the device sets the corresponding bit in the status word. This situation is
especially likely to occur if external factors (required torque, voltage to motor too low)
prevent the device from achieving the target rpm
By setting SDO #2005 to 0 the drag error monitoring can be disabled.
4.8
Drag error correction
With SDO #2046 the drag error correction can be enabled. With this feature enabled,
the drive will raise or lower the target speed proportional to the drag error by the
configured value. The drive attempts under consideration of the configured maximum
current to compensate the drag error which has developped by controlling the target
speed to a value which lays slightly above or below the specified value of the target
speed (SDO #2012).
By setting SDO #2046 to 0 the drag error correction can be disabled.
Drag error monitoring and correction take effect always except during a braking
operation when approaching a target position or when aborting a positioning. The
actual target speed when accelerating is determined by the actual speed at the
beginning of the positioning and the acceleration setting (SDO #201C).
4.9
Abort run when the master fails
If the connection to the master is interrupted during a positioning run, the master
cannot abort an actual run. In order to generate an automatic run abort in this case,
there’s a timeout mechanism with the help of the Sync Manager Wachdog which is
implemented in the EtherCAT master. If the drive doesn’t receive a SYNC event
within a specified time, the drive will abort any positioning.
