NORD Drivesystems BU0550 - Manual (Page 43)

3 AWL (Instruction List, IL)
BU 0550 GB-0813 43
3.5 Function blocks
Function blocks are small pograms, which can save their status values in internal variables. Because of this,
a separate instance must be created in the NORDCON variable list for each function block. E.g. if a timer is
to monitor 3 times in parallel, it must also be set up three times in the list of variables.
Call-up of a function block: „Cal Function block“ (E.g. Cal Timer)
NOTE
Function blocks MUST be called up cyclically! This is important, as most functions in the
function block are not processed within a single cycle.
3.5.1 Standard
Function block Explanation
CTD Downward counter
CTU Upward counter
CTUD Upward and downward counter
SR Bi-stable function, set dominant
RS Bi-stable function, reset dominant
R_TRIG Flank detection, rising flank
F_TRIG Flank detection, falling flank
TON Switch-on delay
TOF Switch-off delay
TP Time pulse
Table 58 Overview of standard library