Configuration Notes:  
You can connect a SIMATIC S7-200 CPU with different types of HMI devices. Here you must take into account differences in communications protocols, baud rates and the number of connections possible. The HMI device always plays the active part in the communication. This entry covers the following two aspects:

• One HMI component can communicate simultaneously with multiple SIMATIC S7-200 CPUs
• One SIMATIC S7-200 CPU can communicate simultaneously with multiple HMI components

One HMI component with multiple SIMATIC S7-200 CPUs
Below is an overview of HMI components that can be connected with the SIMATIC S7-200. In the following table "Number of S7-200s" stands for the maximum number of S7-200 controllers that can be parameterized with the configuration tool. Unless otherwise marked in the table the maximum baud rate is

• 187.5 Kbit/s with PPI protocol
• 12.0 Mbit/s with MPI protocol

Note:  
An MPI master cannot usually access a PPI master in the same network.

One SIMATIC S7-200 CPU with multiple HMI components
Communication can be via the MPI or PPI protocol.

• In the case of the MPI protocol the CPU communicates with each HMI device via a separate connection. This effectively avoids communication problems. However, the number of HMI devices that you can connect to an S7-200 CPU is greatly limited and depends on the type of CPU. The following table gives an overview.
   

  MPI (DP/T)	Number of HMI comp. CPU Port 0	Max. baud rate CPU Port 0	Number of HMI comp. CPU Port 1	Max. baud rate CPU Port 1	Number of HMI comp. EM 277 Port
  CPU 212 (as from firmware 1.1)	3	19.2 kbit/s	-	-	-
  CPU 214 (as from firmware 1.1)	3	19.2 kbit/s	-	-	-
  CPU 215	3	19.2 kbit/s	5	12 Mbit/s	-
  CPU 216	3	19.2 kbit/s	3	19.2 kbit/s	-
  CPU 221	3	187.5 kbit/s	-	-	-
  CPU 222	3	187.5 kbit/s	-	-	-
  CPU 224	3	187.5 kbit/s	-	-	-
  CPU 224XP	3	187.5 kbit/s	3	187.5 kbit/s
  CPU 226	3	187.5 kbit/s	3	187.5 kbit/s	-
  EM 277	-	-	-	-	5 /  max.12 Mbit/s

Special case:
You can connect up to 3 pushbutton panels of the same type (PP7, PP 17-I or PP 17-II); these then all have the same functionality. You assign parameters to the pushbutton panels via the data block of the controller. S7-200 has only one data block and therefore multiple functions cannot be provided for the panels (Entry ID: 691006).

Note: 
Only one TP 070 without any other nodes may be connected to each CPU interface.

• In the case of the PPI protocol, you can theoretically connect 32 nodes, that is a maximum of 32 HMI devices. However, with PPI in one time interval there is only ever one logical connection between the nodes (time multiplex), which is established and disconnected for each communication. The baud rate is max. 187 kbit/s. This practically reduces the number of HMI devices to three per interface.
  Now, in PPI mode, if several HMI devices (PPI masters) access the CPU (PPI slave), it might happen that an HMI device constantly arrives at the CPU that is occupied by another HMI device (or by another PPI master) and is no longer updated. In this case, you should increase the update cycles of the HMI devices. You do this in the relevant configuration tools of the HMI devices or with the text displays TD 100/200(C) in the Micro/WIN text display wizard.
  Use Advanced PPI if the master concerned supports it. This type of protocol uses a separate connection like MPI. For example, when setting the PG/PC interface in Micro/WIN, you can select Advanced PPI when choosing a PPI connection.

More information on communication protocols of the S7-200 is available in the "S7-200 System Manual", chapter 7 - Communicating over a Network, in Entry ID: 1109582 .