Toshiba T2N - Manual (Page 124)

2.INTERNAL OPERATIONS
User’s manual 111
Peripheral support processing interprets the request commands from the periphrals
(programmer, computer link, data transmission module), process the requests
and responds.
Peripheral support processing time is limited up to 2.5ms per one scan so that
scan time is as constant as possible. If it takes more than 2.5ms to process
peripheral support, this processing is stopped once within 2.5ms and remained
processing is continuously performed in the next scan.
SCAN
*) When 2 or more request commands are received simultaneously from the
request source, the processing priority is as follows.
Programmer Port > Communication port > TOSLINE-S20LP
(Computer Link)
As for data link processing, it may take 0.5ms at the worst case
in addition to the above.
When special relay S158 is ON, peripheral support processing time is not
limited and takes place in one scan.
It results in swift response for the peripherals although the scan time is
extended.
Response of the T2N can be delayed on the communication port using SW57.
2.5
Peripheral support
S0040 (0.1sec)
S0041 (0.2sec)
S0042 (0.4sec)
S0043 (0.8sec)
S0044 (1.0sec)
S0045 (2.0sec)
S0046 (4.0sec)
S0047 (8.0sec)
···
···
···
···
···
···
4.0sec
0.8sec
Mode I/O Timer Mode Peripheral Support User program
2.5ms
(max.)