Siemens C79000-Z7076-C552-01 Manual De Usuario

New Functions in Version V4.02

11

Supplement to the STEP 7 User Manual V4.0
C79000-Z7076-C552-01

If you wish to connect an S7-200 to the MPI subnet (in addition to programming
devices, operating panels, or S7-300/400s), you must select a transmission rate of
19.2 Kbps in the properties dialog box for the MPI subnet.

The following restrictions apply:

A maximum of 8 nodes are permitted

(CPUs, programming devices/operator panels, communications processors/
function modules with separate MPI addresses (each node must be able to
support 19.2 Kbps)).

Global data communication between these nodes is impossible.

Only certain S7-200 devices can be connected (see S7-200 System Manual).

In previous versions of STEP 7, the user could define symbols which differed from
one another only in the case used for individual characters. This has been changed
in STEP 7, V4.02. From this version onwards, it will no longer be possible to
distinguish between symbols created in upper and lower case.

This change was made in response to the wishes of our customers, and will greatly
reduce the risk of errors occurring in a program. The restrictions which have been
made to the symbol definition also support the aims of the PLCopen forum to
define a standard for transferable programs.

A symbol definition based solely on the distinction between upper and lower case
characters is now no longer supported. For example, in previous versions the
following definition was possible in the symbol table:

Motor1 = I 0.0

motor1 = I 1.0

The symbols were distinguished on the basis of the case of the first letter. This
type of differentiation carries with it a significant risk of confusion. The new
definition eliminates this possible source of errors.