VIPA System 300S - Communication; FC;SFC 217 - SER_SND - Send to Ptp; FC;SFC 218 - SER_RCV - Receive from Ptp; Protocols and Procedures

7.5 Communication
7.5.1
FC/SFC 217 - SER_SND - Send to PtP
This block sends data via the serial interface. The repeated call of the
FC/SFC 217 SER_SND delivers a return value for 3964R, USS and
Modbus via RETVAL that contains, among other things, recent infor-
mation about the acknowledgement of the partner station. The proto-
cols USS and Modbus require to evaluate the receipt telegram by
calling the FC/SFC 218 SER_RCV after SER_SND.
7.5.2 FC/SFC 218 - SER_RCV - Receive from PtP
This block receives data via the serial interface. Using the FC/SFC
218 SER_RCV after SER_SND with the protocols USS and Modbus
the acknowledgement telegram can be read.
More information about the usage of these blocks may
be found in the manual "SPEED7 Operation List" from
VIP
A.
7.6 Protocols and procedures
The CPU supports the following protocols and procedures:
n ASCII communication
n STX/ETX
n 3964R
n USS
n Modbus
ASCII data communication is one of the simple forms of data
exchange. Incoming characters are transferred 1 to 1. At ASCII, with
every cycle the read FC/SFC is used to store the data that is in the
buf
fer at request time in a parameterized receive data block. If a tele-
gram is spread over various cycles, the data is overwritten. There is
no reception acknowledgement. The communication procedure has to
be controlled by the concerning user application. An according
Receive_ASCII FB may be found within the VIPA library in the service
area of www.vipa.com.
STX/ETX is a simple protocol with start and end ID, where STX
stands for Start of Text and ETX for End of Text.
Overview
ASCII
STX/ETX
VIPA System 300S Deployment PtP communication
Protocols and procedures
HB140 | CPU | 314-6CF03 | GB | 16-43 183