Elmo HARmonica, HARSFEN0602 software manual 186, Limit switches, Connecting an external brake

HARSFEN0602ElmoHARmonicaSoftwareManual PRELIMINARYDRAFT

attempts are made 10msec after the last motor shutdown, or 10msec after the last failure MO=1.

For safety reasons, we recommend to program the Inhibit function as "active low". That prevents incidental motor starts when the input pin is disconnected, or its driving source is powered-down.

14.5Limit switches

The Harmonica has 6 digital input pins. Each of the pins may be associated to a different function. A pin may function as a general-purpose input, or it can function as a motion limiter.

As a motion limiter, a digital input can stop the motion via the Stop-Manager, stop the Reference Generator, or limit the motion to a single direction.

In addition to stopping the motion, the digital input can activate an automatic routine in the user program.

Refer IL[N] in the Command Reference Manual to learn about function association to input pins.

14.6Connecting an external brake

Connecting an electrical brake to a motor helps safety where:

The load is unbalanced, and moves by its own weight when the motor is off. Motor freewheeling can't be tolerated in malfunction cases.

Extreme motor deceleration is required in response to emergency event. The brake activation must be synchronized to the motor-on/motor-off process.

If the brake is engaged too much time after MO=0, the motor may "run away".

•If the brake is released only after the motor is on, then if a position error existed, the

position controller integrated it. When the brake completely releases, the motor may jump.

The Harmonica can program a digital output as a "brake" output – refer the OL[N] command.

The brake output must be connected as follows:

DC Brake relay - Normally

Engaged

Harmonica

Output Connector

opto-coupler pins

Figure 38: Brake output connection

The brake must be engaged when there is no current in the brake coil.

The brake relay coil must be equipped with a freewheeling diode.

•For the current and voltage rating of the Harmonica connector pins, please consult

the Harmonica Manual.

The normal waveforms for brake activation are depicted in Figure 39.

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