- General Electric Computer Accessories User Manual

GEH-6385 Reference and Troubleshooting, 2300 V Drives Chapter 4 Wizards •
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• 4-37
Pulse Test: Timer Configuration
The Pulse Test allows up to two voltage pulses to be commanded and produced by
the power bridge. The duration of the voltage pulses, and the duration of the current
decay time between the pulses and after the pulses, is specified by the pulse test
timer parameters Pulse 1 on time, Pulse 2 on time, Mid pulse off time, and Post pulse
off time.
The diagram below shows a Pulse Test profile and indicates how the timer
parameters are defined.
Off
Park
Pulse
Time
Pulse 1
on time
Mid pulse
off time
Pulse 2
on time
Post pulse
off time
All the timer parameters have units of seconds. If any of the parameters equals zero,
the corresponding pulse on or off time is skipped during the Pulse Test.
The user should keep several issues in mind when specifying these times. First it is
possible for large currents to develop in the bridge as result of these pulses. The
power bridge will protect itself against excessively large currents by declaring an
IOC fault. Any fault will abort the pulse test sequence and require you to perform a
fault reset before another pulse can be commanded. The second issue is that there are
several constraints which the pulse test wizard must deal with when issuing pulses.
Among these are minimum pulse widths, lockout times and transition constraints.
The wizard must always observe these constraints. As a result you may not get the
exact pulse you command or in some cases you may get no pulse at all. For instance,
if you declare a pulse that is smaller than the required minimum pulse then you will
get no pulse. Finally you should be aware that the pulse test wizard always schedules
the end of the mid pulse off time to occur on a task 1 boundary. This is the pivot
point of the sequence and all other timings are computed from this point.
Pulse Test: Operation
The Pulse Test is a diagnostic test that produces a current pulse in the power bridge
and load.
After specifying the Pulse Test configuration parameters, click on the Execute button
to invoke the Pulse Test.
Remaining Parameter Setup
The Remaining Parameter Setup wizard directs configuration of parameters that
cannot be assigned default values during the commissioning process. It is
recommended that the control be allowed to calculate the default parameter settings.