ABB 07CR41 Operating Manual page 88

3
Basic unit cycle time; KD 00,00
The basic unit program is processed cyclically in the time intervals stated by the set cycle time.
The value is given in milliseconds.
The cycle time for a master basic unit is between 0 and 100 ms, only multiples of 5 are
-
allowed.
The cycle time for a slave or stand-alone basic unit is between 0 and 250 ms.
-
If the value 0 is selected, the cycle time is the minimum time required by the basic unit for
each cycle. In this case, the cycle time is not constant.
Calculating the cycle time:
The cycle time Tc can be calculated by the user with the following formula:
Tc ≥ Tb + Tp
with Tb = transfer time of CS31 system bus
and Tp = programming processing time.
The program processing time is the time obtained when you add together the processing time
of all functions in the user program (a list of all the times can be found in the documentation for
the 907 PC 331 programming software).
The program processing time for 1 KB is generally:
0.4 ms with 100 % digital instructions
1.2 ms with 65 % digital instructions and 35 % word instructions.
The bus transmission time is calculated from the installation configuration. This involves
adding the times of all units on the bus. The overall time for extensible remote units is
calculated by adding the unit time to the times for the connected extensions (see the following
table)
Default value: 10 ms
Programming 5 – 16
Advant Controller AC 31 / Issued: 01.99