69
Powering Up and Powering Down the System
Stop Function If a fault occurs the output stage of the servo amplifier is switched off and the
Fault RA/RB contact is opened. In addition, a global error signal can be give n out at
one of the digital outputs (terminals X3/16 and X3/17). These signals can be used
by the higher-level control to finish the current PLC cycle or to shut down the drive
(with additional brake or similar.).
Instruments which are equipped with a selected "Brake" function use a special
sequence for switching off the output stage.
The Stop functions are defined in EN 60204 (VDE 0113), Para. 9.2.2, 9.2.5.3.
There are three categories of Stop functions:
lCategory 0: Shut down by immediately switching off the sup ply of energy to the
drive machinery (i.e an uncontrolled shut-down);
lCategory 1: A controlled shut-down, during which the supply of energy to the
drive machinery is maintained to perform the shut-down, and where the energy
supply is only interrupted when the shut-down has been completed;
lCategory 2: A controlled shut-down, where the supply of energy to the drive
machinery is maintained.
Every machine must be equipped with a Stop function to Category 0. Stop
functions to Categories I and/or 2 must be provided if the safety or functional
requirements of the machine make this necessary.
Emergency Stop
strategies The Emergency Stop function is defined in EN 60204 (VDE 0113), Para. 9.2.5.4.
Implementation of the Emergency Stop function:
lCategory 0: The controller is switched to "disable", the electrical supply
(400VAC) is disconnected.
The motor must be held by an electromagnetic hol ding device (brake).
In multiaxis systems with connected DC-link bus (intermediate circuit) the
motor leads have to be disconnected by a changeover switch and short-
circuited by resistors connected in a star configuration.
lCategory 1: If hazardous conditions can result from an emergency stop switch-
off with an unbraked run-down, then the drive can be switched off by a
controlled shut-down.
Stop Category 1 permits electromotive braking with a switch-off when zero
speed has been reached. Safe shut-down can be achi eved, when the loss of
the mains supply is not rated as a fault and the control takes over the disabling
of the servo amplifier.
In the normal situation, only the supply power is switched off in a safe manner.
The 24V auxiliary supply remains switched on.