Siemens SIMATIC CP 340 User Manual

Communication using function blocks
6.6 Delete receive buffer, FB12 "P_RESET"
PtP coupling and configuration of CP 340
Manual, 04/2011, A5E00369892-03
121
6.6 Delete receive buffer, FB12 "P_RESET"
P_RESET FB
The P_RESET FB deletes the entire receive buffer of the CP 340. All saved frames will be
discarded. Any frame that is incoming at the time when the P_RESET FB is called will be
saved.
The FB is activated by a positive edge at the REQ input. The job can run over several calls
(program cycles).
The LADDR parameter specifies the address of the CP 340 to be addressed.
Error display on the P_RESET FB
The DONE output shows "job completed without errors". ERROR indicates whether an error
has occurred. If there was an error, the corresponding event number is displayed in
STATUS. If no error arises, the STATUS has the value 0. If an error arises the binary result
BR is reset. If the block is terminated without errors, the binary result has the status "1".
Note
The P_RESET FB function block does not have a parameter check, which means that if
there are invalid parameters, the CPU may switch to STOP mode.
STL representation LAD representation
CALL P_RESET, I_P_RESET
REQ: =
LADDR: =
DONE: =
ERROR: =
STATUS: =
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5(4   '21(
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Note
The EN and ENO parameters are only present in the graphical representation (LAD or FBD).
The block is started with EN = TRUE. If the function ends without an error, ENO = TRUE is
set. To process these parameters, the compiler uses the binary result.
The binary result is set to signal state "1" if the block was terminated without errors. If there
was an error, the binary result is set to "0".

Siemens SIMATIC CP 340 Specifications

General

Type	Communications processor
Model	CP 340
Product type designation	CP 340
Supply voltage	24 V DC
Power supply	24 V DC
Operating temperature	0 to 60 °C
Current consumption	150 mA
Temperature Range	0 to 60 °C
Dimensions	40 mm x 120 mm x 120 mm
Weight	0.5 kg

Summary

Product Description

CP 340 Uses and Functionality

Explains the purpose, functionality, and module variants of the CP 340 for data exchange.

Hardware and Software Components for PtP Connection

Lists essential hardware and software components required for establishing point-to-point connections.

Serial Interface Properties

Details technical specifications for RS 232C, 20mA-TTY, and X27 (RS 422/485) interfaces.

Basic Principles of Serial Data Transmission

Transmission Integrity

Covers data integrity aspects for Printer, ASCII, and 3964(R) drivers.

Data Transmission with the 3964(R) Procedure

Details control characters, block checksums, sending, receiving, and error handling for 3964(R).

Data Transfer using the ASCII Driver

Explains ASCII driver use, RS 232C signals, flow control, and end criteria.

Starting up the CP 340

Step Sequence for Commissioning

Outlines the order of operations required for commissioning the CP 340.

Installation and Configuration

Describes integrating, configuring via STEP 7, and assigning parameters to the CP 340.

Mounting the CP 340

Installing and Removing the CP 340

Provides step-by-step instructions for mounting and dismounting the CP 340.

Configuring and Parameterizing the CP 340

Parameterization Options

Lists configuration options for CP 340 variants using STEP 7 or the parameter assignment interface.

Parameterizing Communications Protocols

Explains how to supply CP 340 interface with parameters and configure message texts.

Configuring the CP 340

Explains how to inform the programmable controller about the CP 340's presence and its address.

Managing Parameter Data

Covers saving, downloading, and managing configuration and parameterization data.

Download of Firmware Updates

Provides instructions for updating the CP 340 firmware using HW Config.

Communication using function blocks

Communication via Function Blocks

Explains how communication occurs between CPU, CP 340, and communication partners via function blocks.

Overview of Function Blocks

Lists and describes function blocks (P_RCV, P_SEND, P_PRINT, V24_STAT, V24_SET) for CP 340 communication.

Using Function Blocks for Connecting to Communications Processor

Details using P_SEND and P_RCV for sending and receiving data between S7 and partners.

Using Function Blocks for Outputting Message Texts to Printer

Explains the P_PRINT FB for sending message texts and variables to a printer.

Using Function Blocks for RS 232C Signals

Covers V24_STAT for reading and V24_SET for controlling RS 232C signals.

Diagnostics with the CP 340

Diagnostics Messages of Function Blocks

Diagnostics by Means of Diagnostic Buffer

Connecting Cables

RS 232C Interface Connecting Cables

20mA TTY Interface Connecting Cables

X27 (RS 422/485) Interface Connecting Cables