Computer Drive Installation Instructions

12 Functional Descriptions 08.96

12.33.3 Current setpoint filter

Possible filter combinations

Filter 4 Filter 3 Filter 2 Filter 1 MD 1201

PT2 PT2 PT2 PT2 = 0 0000

PT2 PT2 PT2 BS = 1 0001

PT2 PT2 BS PT2 0010

PT2 PT2 BS BS 0011

PT2 BS PT2 PT2 0100

PT2 BS PT2 BS 0101

PT2 BS BS PT2 0110

PT2 BS BS BS 0111

BS PT2 PT2 PT2 1000

BS PT2 PT2 BS 1001

BS PT2 BS PT2 1010

BS PT2 BS BS 1011

BS BS PT2 PT2 1101

BS BS PT2 BS 1101

BS BS BS PT2 1110

BS BS BS BS 1111

Note

Filter 1 is configured as a low-pass filter as standard.

12.33.3.2 Scope of application of low pass as current setpoint filter

Low-pass filters must be dimensioned such that resonance is kept reliably low while the filter

effect on the fundamental frequency range is minimized.

Filter in the case of resonance in the fundamental frequency range

Resonance in the fundamental frequency range can normally be restricted by means of control

parameters.

Note

Smoothing filters have a negative phase rotation (low-pass generally, bandstop for f < fs, fs

= blocking frequency). This phase rotation can reduce the stability margin of the fundamental

frequency range.

When a filter is used, therefore, the objective must be to obtain the optimum from

• desired damping action and

• minimum possible filter effects on the fundamental frequency range.

12–340

SINUMERIK 840C (IA)