Siemens SIMATIC S7-1200 - Page 802

Communication
11.1 Asynchronous communication connections
S7-1200 Programmable controller
802 System Manual, V4.2, 09/2016, A5E02486680-AK
Available connections
The CPU supports the following number of maximum simultaneous, asynchronous
communication connections for PROFINET and PROFIBUS. The maximum number of
connection resources allocated to each category are fixed; you cannot change these values.
However, you can configure the 6 "Free available connections" to increase the number of
any category as required by your application.
Note
The total number of S7
-1200 communication connections does not increase when you add
CM/CP modules.
Based upon the allocated connection resources, the following number of connections per
device are available:
Programming
terminal (PG)
Human Machine
Interface (HMI)
GET/PUT
client/server
Open User
Communications
Web browser
Maximum
number of
connection
resources
3
(guaranteed to
support
1 PG device)
12
(guaranteed to
support
4 HMI devices)
8 8 30
(guaranteed to
support
3 web browsers)
For an example, a PG has 3 available connection resources. Depending on the current PG
functions in use, the PG might actually use 1, 2, or 3 of its available connection resources. In
the S7-1200, you are always guaranteed at least 1 PG; however, no more than 1 PG is
allowed.
Another example is the number of HMIs, as shown in the figure below. HMIs have 12
available connection resources. Depending on what HMI type or model that you have and
the HMI functions that you use, each HMI might actually use 1, 2, or 3 of its available
connection resources. Given the number of available connection resources being used, it
may be possible to use more than 4 HMIs at one time. However, you are always guaranteed
at least 4 HMIs. An HMI can use its available connection resources (1 each for a total of 3)
for the following functions:
● Reading
● Writing
● Alarming plus diagnostics