Siemens SINAMICS S120 Function Manual page 187

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Table of Contents

Central measuring with/without handshake

Both measuring procedures have the following points in common:

● Setting the input terminal in p0680.

● Signal source, synchronization signal in p0681.

● Signal source, control word probe p0682.

● Transfer with the communication interface PROFIdrive.

● Synchronizing and monitoring isochronous PROFIdrive

● Prerequisite for measurements is the synchronization between the control and drive.

● Setpoint transfer at start time To and actual value transfer at instant in time Ti in the

PROFIBUS cycle (max. 8 ms).

● Time stamp: Format (drive increments, NC decrements)

● Each valid time stamp in the drive is incremented by 1 in order to make a differentiation

between a valid measuring time zero and an invalid time format. This increment is removed

again by the higher-level control.

● The value "0" in the interface is an invalid time format and indicates that a measured value

is not available.

● Sequencer for the control/status word processing

● Monitoring functions (sign of life)

Time-critical data transfer

The status information E_DIGITAL and A_DIGITAL in telegrams 39x are not subject to any

precise time restraints according to the specifications. The transfer of E_DIGITAL and the

output of A_DIGITAL are realized independently of the PROFIBUS cycle with the PROFIdrive

PZD sampling time according to p2048. Depending on the module, this can be set to between

1 ms and 16 ms. As a consequence, dead times must be expected for the transfer of output

values and the feedback signal of input values.

Although the probe status word MT_ZSW is identical with the content of E_DIGITAL, it is

however directly transferred in PZDs. As a consequence, for time-critical applications

measuring probes or cams should be used.

Central measuring with handshake

With p0684 = 0, you activate the evaluation procedure with handshake for the central probe

evaluation. You can evaluate a maximum of one positive and/or negative edge per probe within

four DP cycles.

Drive functions

Function Manual, 06/2019, 6SL3097-5AB00-0BP2

= PROFIBUS cycle (also DP cycle)

Servo control

5.22 Central probe evaluation