Step drive positioning problem

[misa007]

We use step drive (Siemens 4NM) together with PLC 313C-2DP and FM353 module (+ power unit for stepdrive).

Proces description:

- stepdrive 4NM,

- velocity 360 rpm (gearbox i=3),

- impuls per rotation 5000 imp,

- rotary axis,

- step drive is running, after achieved temperature of the proces step drive go 9,2sec after elapsed time step drive is stopping on inductiv sensor.

In main program OB1 we make run stepdrive. The we use HW INT for rising edge of inductiv sensor (this rising edge make stop stepdrive + other conditions).

We have problem with stopping motor on inductive sensor.

After achieved rising edge of inductive sensor motor is stopping after 90ms approximately (this time is still same - deviation only 6 degries).

 

[misa007]

Step drive more specification

description for use components:​

SIMATIC S7-313C-2DP 6ES7313-6CE01-0AB0
​

FM 353 6ES7353-1AH01-0AE0
​

FM STEPDRIVE 6SN1227-2ED10-0HA0
​

SIMOSTEP 1FL3042-0AC31-0BK0
​

gearbox i=3, Berger Lahr (PL50/PL85) Nr. 029920010030. (0,33 kg.cm2, riadial 500N, axial 250N, efficiency 96%)​

Velocity: on axis of motor 360 rpm,​

on output side of gearbox 120 rpm, ​

​

Application short description:​

1. on old machine (with Berger Lahr control system we don´t have this problem - but this control system is too old and we now make displacement with S7 control system)​

2. Motor is running on speed 360 rpm, process speed is 120 rpm,​

3. Motor is still running, after comming signal of reached temperature (on PLC input - this signal can arrive in different time, for each start), then motor go next 9,2sec, after end this time motor must stop on inductiv sensor (realized with HW INT (rising edge of inductiv sensor)). ​

​

Actual state of process:​

1. Speed is without problem,​

2. After timer of 9,2sec is done, and arrive HW INT from inductiv sensor motor is stop after (from 19 to 25) degree later. That means too late for our application. We must stop on inductiv sensor (must stay lightning)​