'Encoder increments' sets the internal position resolution per motor revolution in an application-specific manner. This value is related to the actual position detection with the motor encoder (objects 0x2221.1, 0x2253).

 

At analog encoder evaluation of sine and cosine signals, the incoming signals in the inverter are first converted into square-wave signals and the edges are evaluated (factor 4). In addition, the sine wave and the cosine signal are recorded analogously and from this the analogue angle (arctan) is determined within a sinus period. With this angle, the resolution can be increased by the factor PV (position refinement). Each quarter period is subdivided into a maximum of 2048 measuring steps, thereby refining the position.

Formula: Determination of the motor encoder resolution for sine encoders (I-type encoder)

0x2074 = 4 x 0x2218 x PV

PV = position refinement = (1 ... 2048, integer!)

Object 0x2218 'Sinus encoder period'

Example:

0x2218 = 50 (type plate), PV = 100 selected

0x2074 = 20000 incr./motor revolution

Formula: Motor encoder resolution for the use of absolute encoders (S-, T-, E-, F-, U-, V-type encoder)

0x2074 = 4 x 0x2218 x PV

PV = position refinement = 1 ... 2048, integer!

Objects 0x2218 'Sinus encoder period'

Example:

0x2218 = 1024 (type plate), PV = 20 selected

0x2074 = 81920 incr./motor revolution

Formula: Motor encoder resolution for the use of absolute encoders (P-, Q-, Y-type encoder)

0x2074 = PV x MPU/2048

PV = position refinement = 1, 2, 3 ... integer!

MPU = determine the MPU value from the nameplate or from the motor data sheet:

Periodes / revolution (data sheet or type plate)	MPU (measuring steps / revolution - digital resolution)	0x2074 example value
16 P./Rev.	262144 Inkrements	0x2074 = 262144, with PV = 2048
32 P./Rev.	524288 Inkrements	0x2074 = 524288, with PV = 2048

 

A position refinement factor of 2048 corresponds to the real resolution of the encoder.   If required, you can use higher values to adapt the encoder resolution to the application. A position refinement factor > 2048 does not improve the resolution of the encoder system.