NORD Drivesystems BU0510 - Manual (Page 25)

3 Description of function
BU 0510 GB-3911 Subject to technical alterations 25
3.2.2.3 Resetting absolute encoders
With the exception of SSI encoders, absolute encoders can be set to the value "0" or to the value set in P609 [-
02] "Offset Position" via the functions "Reference Point Run"(see 3.2.1.1).
However, the precision of resetting the encoder position greatly depends on the actual speed of movement,
the bus load, the baud rate (CANopen encoders) and the type of encoder. Therefore it is urgently
recommended that absolute encoders are only reset when they are at a standstill.
With an SSI encoder the position can only be changed via a position offset P609 [-03]. Resetting ("Reset
position" / "Reference Point Run") is not possible.
If both an incremental encoder and an absolute encoder are connected to the frequency inverter, both
encoders are reset by performing the functions "Reference Point Run" or "Reset Position".
3.2.2.4 Parameterisation on the frequency inverter
Communication settings
If a CANopen absolute encoder is used for position detection, the CAN baud rate (P514) and the CAN
address (P515) must be parameterised on both the encoder and the frequency inverter.
NOTE
If an IO extension (e.g. SK TU4- IOE) is also used, it must be noted that the addresses 10 …
13 and 20 … 23 are reserved for this module (For details see Manual BU0200).
After this, the CAN Bus must be supplied with 24V in order to activate communication between all the
connected participants.
For all other absolute encoders such as Endat, SSI, … (SK 540E and above), no communication settings are
required between the frequency inverter and the associated encoder.
Encoder data settings
The resolution of the absolute encoder is set via the parameter P605 "Absolute Encoder":
Parameter Meaning Availability Setting example
P605 [-01] Multi-turn resolution in bits SK 530E and
above
12

4096 Encoder rotations
25Bit
encoder
P605 [-02] Single-turn resolution in bits SK 530E and
above
13  8192
Steps per rotation
P605 [-03] Sin/Cos periods per
rotation (Hiperface) SK 540E and
above
Table 14: Parameter P605 - Setting of encoder resolution for absolute encoders
The relevant settings should be obtained from the data sheet for the absolute encoder.
The absolute encoder is activated via parameter P604 "Encoder Type". Here, a differentiation is made
between normal measurement (for "linear" systems) and "path optimised" measurement (for circulating
systems) (see Section 3.2.4).