Signal Edge Evaluation (1X, 4X) - Siemens Sinamics S120 Function Manual

Hide thumbs Also See for Sinamics S120:

Table of Contents

Signal edge evaluation (1x, 4x)

The "signal edge evaluation" function allows squarewave encoders with higher production

tolerances or older encoders to be used. Using this function, a "steadier" speed actual value

is calculated for encoders with an uneven pulse duty factor of the encoder signals. As a

consequence, you can keep the old motors together with the encoders - for example when

modernizing plants.

Commissioning

● Sets parameters p0437 bit 4 and bit 5 as follows to activate "signal edge evaluation":

Principle of operation

For the 4x evaluation, both the rising and falling edges of a contiguous pulse pair on the A

and B tracks are evaluated.

For the 1x evaluation, only the first or the last edge of a contiguous pulse pair on the A and B

tracks are evaluated.

A 4x evaluation of the pulse encoder signals allows a minimum speed to be detected which

is a factor of 4 lower than for the 1x evaluation. For incremental encoders with uneven pulse

duty factor of the encoder signals or where the encoder signals are not precisely offset by

90°, a 4x evaluation can result in a speed actual value that is somewhat less steady.

The following formula defines the lowest speed where a distinction can be made to 0:

n_min = 60 / (x*p0408) [rpm]

with x = 1 or 4 (x times evaluation)

You can only use the reduction to 1x evaluation in conjunction with the edge zero mark or

without zero mark. Detection with an accuracy of one pulse is no longer possible for zero

marks with "unambiguous range" or distance-coded zero marks.

Drive functions

Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2

Basic functions

6.18 Tolerant encoder monitoring

4 x (factory setting)

Show Quick Links

Table of Contents