Magnetek HPV 900 Series 2, Техническое руководство

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APPENDIX
– Safe-Off
159
Appendix
SAFE-OFF
Safe-Off Functional Overview
To summarize the feature, the Safe-Off function is yet another way to positively disable the drive so it
cannot cause a motor runaway. It uses a switch to change terminal TB1-
26 from “Logic input 9” to a
base enable (BE) function.
1. The Safe-Off input to the drive uses only hardware to positively turn IGBT gating off.
This will only occur when the switch on the control card is set to the BE position.
2.
The DRIVE monitors the status of the signal and the menu selection of what the user
has established for Logic input 9.
3.
If the status of this input does not match the setting for Logic input 9, a “Safe Off
Setup Fault” will be declared
4.
If the C2 menu selection claims that logic input should be used as Safe-Off, but the
logic input status is not what the drive is expecting, then there will be a “Safe Off Setup Fault”,
a “Current Regulator Fault” may occur on running, or the drive may not run at all
5.
If the Safe-Off function is set up correctly and the drive receives other
enabling/command logic to start but the Safe-
Off signal is not yet in the ‘safe to-run’ state, the
drive will not start.
It will not get to a state where regulators are released unless the Safe-Off input becomes high
to match enabling/command signals within 1 second. If the signals do not match after this
time, the drive will declare a Safe-Off Fault (As diagnostic information and to avoid remaining
indefinitely poised to run) or a Current Regulator Fault. The drive will not be allowed to
become engaged with IGBTs disabled. This prevents speed or current integrators from
starting that may cause significant ‘bumps’ when/if IGBT gating should become enabled.
During this time Regulator Release will not be indicated, because the drive has not yet started.
6.
EN81-1 does not indicate any requirement in timing for the drive to become disabled if
safe-off becomes disabled. Since it is an enable/disable function in hardware, it is relatively
fast (micro-seconds). However:

If the drive is not running and receives a Drive Enable and Run command, but NO
Input on logic input 9, it will not begin to fire IGBTs to apply torque to the motor and a
fault will be declared after 1s

If the drive already has a Drive Enable and Run command present, and Logic Input 9
is opened whilst torque is already being applied to the motor, IGBTs will immediately
cease firing and a fault will be declared after 50ms
In any instance, the drive will disable the IGBTs as soon as Logic Input 9 becomes open.
7.
The standard requires that the safe-off function be cycled and verified to be working at
least before every reversal of elevator direction. So it is the car controller circuitry, not the
drive, which performs the function to interrupt the safe-off circuitry and therefore the car
controller which must also verify that the drive has indeed removed gating power when
commanded to do so. One of the drive’s programmable logic outputs can be used to indicate
that the drive recognizes the status of the internal safe-off circuitry in order for the car
controller to verify functionality according to the standards requirements.
8.
In case of the safe-off function disabling the drive while it is running, the drive shall
declare a safe-off fault, along with other expected faults resulting from a crash stop,
depending on speed and drive mode.
Enabling the safe off feature