Ip251_02b_oi_e.doc / Apr-16
Page 19 / 28
Parameter
Description
SSI Baud Rate:
Sets the communication speed of the SSI interface with SSI encoders.
Setting range: 100 Hz to 1MHz.
You are free to set any desired frequency between 0.1 kHz and 1000.0 kHz. For
technical reasons however, in the upper frequency range with Master operation, the
unit will only generate one of the following frequencies accurately:
1 000.0 kHz
888.0 kHz
800.0 kHz
727.0 kHz
666.0 kHz
615.0 kHz
571.0 kHz
533.0 kHz
500.0 kHz
470.0 kHz
444.0 kHz
421.0 kHz
400.0 kHz
380.0 kHz
363.0 kHz
347.0 kHz
333.0 kHz
320.0 kHz
307.0 kHz
296.0 kHz
285.0 kHz
275.0 kHz
266.0 kHz
258.0 kHz
250.0 kHz
With Master operation, therefore other settings will result in generation of the next
upper or lower value according to above list. With all settings < 250.0 kHz the error
between set rate and generated rate becomes negligible.
It is mandatory to set the Baud rate also with Slave operation.
In this case, however, the setting serves only to determine the pause time
for correct synchronizations (pause is detected after 4 clock cycles). The unit
automatically synchronizes with every remote clock signal within the
specified Baud rate range.
SSI Wait Time:
This register sets the waiting time between two SSI telegrams in a range
from 0.001 to 10.000 s. In normal operation, due to processor cycle times,
the real time may vary by 512 µs. with respect to the preset time.
The fastest sequence possible is 1.3 ms at a setting of 0.000.
With Slave operation mode, the distance of the SSI protocols depends on the remote
Master and the SSI Wait Time specifies the distance of evaluation data strings.
Setting to 100 ms results in evaluation of one telegram only every 100 ms, even
though the Master may have transmitted many telegrams more.
Especially with applications of closed-loop control loops, it may be of advantage to
have equidistant updating of the output (DIL switch 7 = OFF). This is possible with
Master mode only and the Wait Time setting (must be >0) directly corresponds to the
time pattern of updates.
