ZES ZIMMER LMG450, Руководство пользователя

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Z E S ZIMMER Electronic Systems GmbH Chapter 9
127
Limit Here you can setup the limits for the events. The instantaneous value of the signal
to be watched is checked against the limit if it is bigger (or smaller) an event is
generated. If a function needs two limits (e.g. Win In) Lim1 is the upper limit and
Lim2 the lower limit.
Slewr Here you can setup the maximum allowed slewrate of the signal. For this you have
3 possible settings:
dSig This is the required signal change in the time interval dt.
dt This is the time interval.
overx This is the width of the slewrate watch window in number of sample
values.
For example you have a signal with a typical rise time of 3.5V in 450
µ
s. In this
case you have to enter 3.5 with dSig and 450
µ
with dt. Herewith you have defined
the steep of the signal: 7.777V/ms or 7.777mV/
µ
s. With a sample interval of about
20
µ
s (20
µ
s *7.777mV/
µ
s = 155.54mV) this is only about 3 bit (in 600V range; 1
bit = 1600Vpeak/32768 = 48.8mV) of the converter resolution. That means, if the
difference between two sample values is bigger than 3 bit you would get an event.
But from several sources you have a small noise on the signal. This would cause
fail events. To prevent this you can use the parameter overx. With it you can
define, that the slewrate is not defined over one sample period but over up to 15. If
you for example choose 15 (15*20
µ
s*7.777mV/
µ
s=2.333V), the signal has to
change 48 bit in this example! So you can use overx to suppress noise effects.
While you are in the Set mode you can use the rotary knob to define the trigger condition.
Move to the desired position and press Enter to mark/unmark the condition. In the left column
you can setup the AND condition. Only if all of this marked events happen at the same time the
result of the AND condition will be true. In the right column you can setup the OR condition.
If one or more of the marked events happen or the result of the AND condition is true you will
get an event.
An event is generated depending on the event type if:
Slewrate the slew rate of the signal is bigger than defined by the Slewr menu.
Win In the signal is <Limit1 and >Limit2
Win Out the signal is >Limit1 or <Limit2
>Limit1 the signal is >Limit1
<Limit1 the signal is <Limit1
>Limit2 the signal is >Limit2
<Limit2 the signal is <Limit2