Note On S7300 Cpu: Connection Resources; Slot Rules For Simatic S7400; Permitted Slots; Number Of Simatic Net Cps Being Operated At The Same Time - Siemens S7-300 Configuration Manual

Characteristics of the Ethernet CPs

2.4 Slot rules for SIMATIC S7400

A PG is required to download the configuration after replacing a module. If the CP supports
the option of saving the configuration data on the CPU, it is also possible to replace a
module without a PG (see CPspecific description).
2.3.5

Note on S7300 CPU: Connection resources

Note that when using older S7300 CPUs (≤ CPU 316), a maximum of 4 S7 type connections
for CP communication are supported. Of these 4 connections, one is reserved for a PG and
another for an OP (HMI = Human Machine Interface). (The newer CPUs (from 10/99
onwards) support 12 and the CPU 3182DP supports 32 S7 connections.)
As a result, the older S7300 CPUs have only 2 "free" S7 connections available. These 2
connections can be used for S7 communication, for PROFIBUSFMS, for longer data or
FETCH, WRITE and TCP connections with Industrial Ethernet.
If you use CPs that support multiplexing of OP connections and S7 communication using
loadable communications blocks, only 1 connection resource is occupied if you use both
services.
Note
Depending on the CP type installed and the services being used, there may be other
restrictions (see CPspecific description in this manual).
2.4 Slot rules for SIMATIC S7400
2.4.1

Permitted slots

An S7400 CP can be inserted both in the central rack and in the expansion rack with a K bus
interface. For information about the number of CPs you can use in total, refer to the
information on the relevant CP in the section "Properties".
In the SIMATIC S7400, there is no set slot assignment for the SIMATIC NET CPs. Slots 2 to
18 are permitted. Remember, however, that slot 1 and, depending on the power supply
module used, also slots 2-3 (and 4 in redundant mode), are occupied by the power supply
modules.
2.4.2

Number of SIMATIC NET CPs being operated at the same time

The number of SIMATIC NET CPs that can be operated simultaneously is limited by the
specific characteristics of the CPU. The exact number can be found in the CPspecific section
of this manual.
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Configuring and commissioning S7 CPs for Industrial Ethernet
Configuration Manual, 09/2013, C79000-G8976-C182-13