Baumer NE230 - Handbuch (Seite 9)

NE230
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Operating instructions
Interface description
NE230 Program 01
1. General information
The serial interface has the same function as counter display and keypad. The interface enables polling data or
altering programmed parameters. Normally the counter is PC-operated when using the interface, reason why in
the following the external device is simply called PC. However, any other device featuring similar characteristics
may be applied.
2. Transmission protocol
Data transmission is sign by sign in ASCII code. Each sign consists of 8 bits. Bit no. 8 is the so-called parity bit,
in case of „no parity“ bit no. 8 will always be transmitted zero. Upon polling data by PC, the counter will give a
corresponding reply by serial interface, provided the data transfer was effected correctly. The sign transmission
starts with the header <STX> and ends with the footer <ETX>. In addition, after <ETX> the counter is sending
<CR> (carriage return) allowing read-in of a complete data block by one command (in standard computer
languages as BASIC).
<STX> is followed by a the designated counter identification. Thus, the counter can be individually addressed in
serial network. After the identification the line (position) to be read or programmed is being defined. Any
programming command is followed by “P” (programming) with the corresponding data (parameters).
The protocol is split into 3 groups as below:
a) Read memory locations (READ instruction):
<STX> identification line <ETX> [<CR>]
b) Programming memory locations (WRITE instruction):
<STX> identification line P data <ETX> [<CR>]
c) Special commands:
<STX> identification parameter <ETX> [<CR>]
<STX> start of text (02Hex)
address 00..99 (device address)
line 01..XX (see operating instructions)
P programming command
data programming data
parameter special commands
<ETX> end of text (03Hex)
<CR> 0DHex (control sign "carriage return")
"CR" not imperative (optional) but always sent
back by counter.
Example:
General
<STX> identification line <ETX> (identification=35; line=02)
Ascii <STX>3502<ETX>
Hex 02H,33H,35H,30H,32H,03H
Important! The space between the individual signs of each command are for optical reasons only. Entering by
PC has to be without space. Control signs (inferior 20Hex) are shown in parentheses. Upon
receiving a void PC protocol NE230 will reply by an error alarm, provided the counter is still capable
of responding (see chapter „error alarms“ on page 6).