User Manual

C. CI interface
C−9
Festo GDCP−SFC−LACI−DN−EN en 0812NH
Note
All length specifications (also velocities and similar) are
saved in millimetres in the controller and are not converted
into the relevant unit of measurement
system until they
are written or read.
Values must be converted to increments before being
transmitted over the CI interface; see section A.3.
C.1.5 Checking the data
Permitted value ranges Transferred parameters and values are checked by the SFC−
LACI before being accepted.
Note
In the case of invalid parameters or values, an error
message will not appear in the response; rather, the re
ceived value will always be r
eturned (Echo).
Recommendation
Check that values have been written correctly by
downloading the current contents of the object with a
subsequent Read command. The h
igher level controller must
compare the sent command with the Echo" from the
SFC−LACI and check the checksum.
Note
The following applies when writing the objects:
 Discrete values (values from a value list):
an invalid value will not be accepted; the previo
usly
valid value will be retained.
 Continuous values (e.g. lengths, speeds, etc.):
an impermissible value will be limited to the nearest
perm
itted value.