Siemens SIMATIC NET S7-300 User Manual

7 Programming FCs (Functions) and FBs for S7 Ethernet CPs
A-232
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
7.7 FB88 PN_InOut / FB90 PN_InOut_Fast blocks for
PROFINET CBA
How It Works
The task of function block FB88 / FB90 is to transfer data from the interface DB to
the CP and from the CP to the interface DB. The interface DB itself is the interface
to the user program.
FB88 / FB90 is called cyclically. It is also possible to call FB88 /FB90 more than
once in a cycle.
At its interface, FB88 /FB90 only needs to be supplied with the module address of
the CP.
To ensure data consistency, you can only modify the data to be transferred or start
to read the received data when the job is completed (DONE=1 or ERROR=1).
As soon as DONE=1 or ERROR=1 are set, the transfer is complete or has been
terminated with an error message. Data can now be evaluated or set again. Data
will only be transferred with the next call.
In your user program, make sure that on completion of data transfer FB88 /FB90 is
called again only after all the input data have been read and all output data have
been written to the interface DB.
Calling the FB88 / FB90 blocks time-driven is permitted in principle. Refer to the
notes on this mode later in this chapter.
Differences between FB88 and FB90
The activities of the function blocks FB90 and FB88 on the interface to the user
program are largely identical. You can use FB90 with certain CP/CPU types with
an S7-400; refer to the information in the manual of the CP.
If FB90 is approved for the CP type being used, we recommend that you use it.
This allows you to achieve shorter reaction times than with FB88. However, note
the constraints regarding its use.
The following points apply:
 The interface parameters are identical;
 For FB90, there are several additional codes in the STATUS parameter;
 With some errors, there are different codes in the STATUS parameter of FB88
and FB90;
 There are differences in the configuration limits of the interface DB (see
relevant manual).

Siemens SIMATIC NET S7-300 Specifications

General

Product Type Designation	SIMATIC NET S7-300
Mounting	DIN rail mounting
Protection Class	IP20
CPU Models	Various models available (e.g., CPU 312, CPU 314)
Communication Interfaces	MPI, PROFIBUS DP
Power Supply	24 V DC power supply required. Different power supply modules available.
I/O Modules	Digital input modules, digital output modules, analog input modules, analog output modules
Programming	STEP 7 software
Supply Voltage	24V DC or 120/230V AC (depending on model)
Digital Inputs	Available via digital input modules
Digital Outputs	Available via digital output modules
Analog Inputs	Available via analog input modules
Analog Outputs	Available via analog output modules
Communication Functions	MPI, PROFIBUS DP, Ethernet (depending on model)
Protocols	MPI, PROFIBUS DP, TCP/IP (depending on model)
Operating Temperature	0°C to 60°C
Storage Temperature	70 °C
Memory	Depends on CPU model (e.g., 32 KB to 1.5 MB)