Manual Weighing Controller A 810
A.S.T. Angewandte SYSTEM-TECHNIK GmbH Dresden
Page
75
4. Serial
Interfaces
4.1. Modes of Operation of the Serial Interfaces
Each of five serial interfaces of an A810 terminal is suited for the asynchronous exchange of data in full
duplex mode.
4.2. Exchange of a Character
4.2.1. Data Exchange Parameters
The following data exchange parameters are available and have to be set in line with the characteristics
of the peripheral device:
Baud rate, Bit/s:
1200, 2400, 4800, 9600, 14400, 19200, 38400, 76800
Data bits, parity:
8Bit, none / 8Bit, even / 8Bit, odd / 7Bit, even / 7Bit, odd
Stop bits:
1
4.2.2. Character Coding
The 7-bit or 8-bit ASCII code is used for the coding of characters depending on the characteristics of the
peripheral device and the mode of data safeguarding. Please pay attention to the following constraints:
The 8-bit code has to be selected when a printer with an 8-bit character set (IBM 2) is used and the 8-bit
characters are exploited in full (umlauts, graphics characters). Data safeguarding by means of block
check sum requires the 7-bit code but this will be the exception since generally the demands of calibration
approval cannot be met when further processing the data by PC. When the 8-bit code shall be used, set
data exchange to 8 bit when commissioning the terminal. Data exchange between a A810 terminal and
an IBM compatible PC requires the 7-bit code (with/without parity bit) or the 8-bit code without parity bit to
be used since the UART modules of a PC can transfer a data frame of no more than 10 bits (including
start and stop bit).
Recommendation:
Always set to 8 bit, no parity unless there are compelling reasons to select
some other mode.
4.2.3. Electrical Implementation of the Serial Interfaces
Table 1 shows the assignment of the physical interfaces to a number of standards. Though any physical
interface can be connected to any logical device, there is a standard assignment identical with the default
configuration when the instrument is supplied.
Interface 0
Interface 1
Interface 2
Interface 3
Interface 4
physical
interface
standard
RS422 / RS485
RS232
RS232
Profibus
/Ethernet
TTY
preferred
assignment to
logical device
measuring BUS
PC
printer 1
SPS/ PC
Table 1