IF52
SSI Wait Time
This register sets the waiting time (gap) between two SSI telegrams in a range
from 0.001 to 10.000 sec. During normal operation, due to processor cycle
times, the real time may vary by 512 µsec. with respect to the preset time. The
fastest sequence possible is 1.3 µsec with a setting of 0.000.
In Slave operation mode, the distance of the SSI protocols depends on the
remote Master and the
specifies the distance of evaluation data
strings. Setting this register to 100 msec results in evaluation of one telegram
only every 100 msec, even though the Master may have transmitted many
telegrams more.
Especially with applications of closed-loop control loops, it may be
advantageous to have fixed updating cycles of the output (DIL switch 7 UPDATE
MODE= OFF). This is possible in Master mode only, and the
setting (it must be > 0) directly corresponds to the time pattern of updates.
The Figure below explains the timing with use of fixed updating cycles mode
when the
item is set to 3 msec.
With fixed updating cycles work mode, the
msec. max.
NOTE
•
The shortest time allowed for fixed updating cycles is 2 msec, due to
internal processing times (
set to 0.001). While your PC is
communicating with the unit, it is 5 msec.
•
The time marks TM1 and TM2 shown in the Figure above can be
displayed using the MONITOR function of the PC operator software. It is
easy to understand that the sum of both times must be equal to the
setting; otherwise you must increase the Baud rate or
choose a longer update cycle. The serial access codes are ,, :3 “ for TM1
and ,, :5 “ for TM2.
•
In critical cases you can reduce the internal processing times of the unit,
by omitting the conversion of serial RS-232 encoder data. For this, just
set parameter
to 00000.
MAN IF52 I_E 1.1.odt
9 - Parameter settings
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