Functions of the board APCI-3xxx
(standard)
46
8.6
TTL inputs and outputs
The board
APCI-3xxx
has 24 TTL channels that are divided into three
ports:
Table 8-1: TTL I/O (ports)
Port
Description
Channel
Port 0
Output
Channel 0-7
Port 1
Input
Channel 8-15
Port 2
Programmable I/O
Channel 16-23
Fig. 8-7: Block diagram of the TTL I/O
8.7
Watchdog
A 16-bit watchdog is available for the analog outputs and for the 24 V
outputs. After its reload value (timeout) the watchdog resets the outputs.
When the watchdog is released, with each setting of the outputs the reload
value is reloaded (triggering). The triggering also can be done directly
through software command without resetting the outputs.
The operating mode can be read back. As time bases for the watchdog three
different clock signals (
μ
s, ms, s) can be used. You can select to release the
wtachdog’s status on the 24 V- outputs 1 and 2.
