172
Digitax ST User Guide
Issue Number: 5
12.22.10 Fast Disable
This bit is a duplicate of parameter Pr
8.09
and reflects the state of the
enable input. With software V01.10.00 and later, if the destination of one
of the drive digital I/O (Pr
8.21
to Pr
8.26
) is set to Pr
6.29
and the I/O is
set as an input, the state of the input does not affect the value of this
parameter as it is protected, however, it does provide a fast disable
function.
The Safe Torque Off input to the drive (T31) disables the drive in
hardware by removing the gate drive signals from the inverter IGBTs and
also disables the drive via the software system. When the drive is
disabled by de-activating the Safe Torque Off input (T31) there can be a
delay of up to 20 ms (typically 8 ms) before the drive is disabled.
However, if a digital I/O is set up to provide the fast disable function it is
possible to disable the drive within 600
μ
s of de-activating the input. To
do this an enable signal should be given to both the Safe Torque Off
input (T31) and to the digital I/O selected for the fast disable function.
The state of the digital I/O including the effect of its associated invert
parameter is ANDed with the Safe Torque Off (T31) to enable the drive.
6.29
Hardware enable
RO
Bit
NC
PT
Ú
OFF (0) or On (1)
Ö
If the safety function of the Safe Torque Off input is required
then there must not be a direct connection between the Safe
Torque Off input (T31) and any other digital I/O on the drive.
If the safety function of the Safe Torque Off input and the fast
disable function is required then the drive should be given
two separate independent enable signals. A safety related
enable from a safe source connected to the Safe Torque Off
input on the drive. A second enable connected to the digital
I/O on the drive selected for the fast disable function. The
circuit must be arranged so that a fault which causes the fast
input to be forced high cannot cause the Safe Torque Off
input to be forced high, including the case where a
component such as a blocking diode has failed.
WARNING
Summary of Contents for Digitax ST
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