Opening The Position Control Loop - HEIDENHAIN TNC 426 PB/M Technical Manual

Table of Contents

position control

If M4581 has been set, the control opens the loops of all axes and of the

spindle, and then performs an NC stop. This makes it possible, for example,

to open the position control loops and at the same time switch off the drives.

As with an external emergency stop, position monitoring is shut off for the

time defined in MP1150.1, and an actual-to-nominal value transfer is executed.

After the time defined in MP1150.1 has expired, position monitoring is again

active, for at least the time defined in MP1150.2.

MP1150.1 = 0 switches position monitoring off! Safe machine operation is

not possible if the position monitoring function is switched off.

Uncontrolled machine movements will not be detected!

If at a standstill or with an external stop, the PLC sets M4581 in the Program

Run, Full Sequence, Program Run, Single Block or Positioning with MDI

operating modes, and then the axes are moved, the Approach position

function will be activated when the PLC resets M4581.

If MP4020 bit 8 = 1, then, if the axes are moved after an emergency stop, the

Approach position function is automatically activated.

If M4580 has been set, an external EMERGENCY STOP (X42, pin 4 "control-

is-ready signal acknowledgement") is not reported to the NC, but rather the

function is executed like M4581.

If the position control loop is opened, the axis release in W1024 is canceled.

Suppress EMERGENCY STOP, open

all position control loops, NC stop

Open all position control loops, NC

stop, activate "Approach position"

Axis release

Bits 0 to 8 correspond to axes 1 to 9

0: Position control loop open

1: Position control loop closed

Time period for which the monitoring function is to remain

off after the fast PLC input defined in MP4130.0 is set

0 to 65.535 [s]

Recommended: 0.2 to 0.5

PLC compatibility

Bit 8 – Behavior after an external emergency stop

0: "Approach position" is not automatically activated

1: "Approach position" is automatically activated

HEIDENHAIN Technical Manual TNC 426, TNC 430