IAI America SCON-CA - Manual (Page 20)

10
10. Limitations on operation of rotary actuator in index mode
Rotary actuators of 360-degree specification can select the normal mode for finite rotations or
the index mode enabling multi-rotation control by using parameter No.79 “Rotational axis mode
selection”. [Refer to Chapter 8 I/O Parameter.]�
The following limitations are applied to the index mode:
1) Controllers of absolute specification cannot select the index mode. If selected, alarm code
0A1 “parameter data error” is issued.
2) Index Mode cannot be selected in Pulse Train Control Mode. It will generate Alarm Code
0A1 “Parameter Error”.
3) The command range in the jog operation with PC software, teaching pendant or PIO signal
is 0 to 360.00�.
4) Pressing is unavailable. The pressing torque can only be set to 0.
5) Do not issue positioning command around 0� repeatedly during movement near 0�. Failure
to follow this may cause the actuator to rotate in the direction reverse to the specified
rotation direction or operate indefinitely.
6) Software stroke limit is invalid in the index mode.
�
11. According to Sequence Program Creation
Please note the following things when creating a sequence program.
When data transfer is necessary between two devices that have a different scan time from each
other, duration more than the longer scan time is required to certainly read the signal. (It is
recommended to have at least twice of the longer scan time for the timer setting to conduct the
reading process on the PLC side safely.)
�
� Operation Image
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
Also, if one tries to read the signal that is being re-written by the other, the signal may be read wrongly.
Make sure to read the signal after the rewriting is complete. (It is recommended to have more than 2 scan
periods to wait.) Make sure not to have the output side to change the output until the other side completes
the reading. Also, a setting is made on the input area not to receive the signal less than a certain time to
prevent a wrong reading of noise. This duration also needs to be considered.�
This controller
(scan time 1msec)
PLC
(e.g. scan time is 20msec)
As shown in the diagram, the input and output
timings of two devices that have different scan
time do not match, of course, when transferring
a signal.
There is no guarantee that PLC would read the
signal as soon as this controller signal turns on.
In such a case, make the setting to read the
signal after a certain time that is longer than the
longer scan time to ensure the reading process
to succeed on the PLC side.
It is the same in the case this controller side
reads the signal.
In such a case, it is recommended to ensure 2
to 4 times of the scan time for the timer setting
margin.
It is risky to have the setting below the scan
time since the timer is also processed in the
scan process.
In the diagram, PLC can only read the input
once in 20msec even though this controller
output once in 1msec.
Because PLC only conducts output process
once in 20msec, this controller identifies the
same output status for that while.
Output
Process
Input
Process