Baumer NE218 - Handbuch (Seite 8)

NE218
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Operating instructions
Interface description
NE218 Program 01
1. General information
A serial interface fulfills the same functionalities as display and counter keypad. The interface is used for data
requests and parameterizing. When utilizing a serial interface, the counter is usually operated by a PC. However,
any other device offering the same functionality will do as well.
2. Transmission protocol
Transmission is performed token by token in ASCII-Code. Every token comprises 8 bit. Bit number 8 is the parity
bit, in case of “no parity” this bit is ever transmitted as 0.
The counter will respond to every PC request via the serial interface, provided data transmission was correct.
The token transmission provides a starting header (start of text) <STX> and an ending footer <ETX> (end of
text). The counter will add affix <CR> (carriage return) after <ETX> to enable read-in of the complete data block
by a single command (for example in high level languages like BASIC).
<STX> is followed by the allocated counter address used to address the counter in the serial network. The ad-
dress is followed by the line (item) to be read out or programmed. A programming command is followed by “P”
(programming) and the data (parameters).
The protocol is subdivided into three groups as specified below:
a) Read memory locations (READ command):
<STX> address line <ETX> [<CR>]
b) Write memory locations (WRITE command):
<STX> address line P data <ETX> [<CR>]
c) Special commands:
<STX> address parameter <ETX> [<CR>]
<STX> Start of Text (02Hex)
Address 00..99 (device address)
Line 01..XX (see parameterization plan)
P programming command
Data Parameters
Parameter Special command
<ETX> End of Text (03Hex)
<CR> 0DHex (control token "carriage return")
"CR" is optional but is ever replied by the counter.
Example:
General < STX> address line <ETX> (address =35; line=02)
Ascii <STX>3502<ETX>
Hex 02H,33H,35H,30H,32H,03H