Baumer NE215 - Handbuch (Seite 11)

NE215
www.baumer.com 11
Description of the open interface
for the electronic controller and monitoring device
NE215 with opened and closed interface
1. General
The open interface is of the RS485 Type. It allows to send the commands as described in the present
documentation to the counter for remote control. The interface allows to call up data and to change the
programming of parameters that are not relevant for the values needing to be calibrated.
In general, the counter is operated with the serial interface from a personal computer; that is why the external
device will be called PC for short in the following. However, it is also possible to use another device with similar
features.
2. Transmission protocol
The transmission is effected character by character in ASCII code. Each character consists of 8 bits. The 8
th bit
is the parity bit, and in case of "no parity", the 8 th bit will always be sent as zero. The counter responds to every
request of the PC via the serial interface if the data has been correctly transmitted.
The transmission of characters is introduced with the start-of-text character <STX> and closed by the end-of-text
character <ETX>. In addition, the counter sends a <CR> (carriage return) after <ETX>. This allows the input of
a complete data block by means of one command (in high-level languages such as BASIC).
After <STX> there will follow an address allotted to the counter, making it possible to specifically address the
counter within a serial network. After the address, please indicate the position that you wish to read out or the
program. In case of a programming command, you will need to enter a "P" (for programming) and the data
(parameters).
The protocols are classified into three groups as indicated below:
a) Reading of the storage locations (READ instruction):
<STX> Address line <ETX> [<CR>]
b) Programming of storage locations (WRITE instruction):
<STX> Address line P [VZ] Data <ETX> [<CR>]
c) Special commands:
<STX> Address parameter <ETX> [<CR>]
<STX> Start of text (02Hex)
Address 00..99 (device address)
Line
01..XX (please refer to operating plan)
P Programming command
D Print command
VZ Plus/Minus sign, only indicated if value is negative
Data Programming data
Parameter Special commands
<ETX> End of text (03Hex)
<CR> 0DHex (control character "carriage return"). "CR" need
not be indicated(optional), will however always be
returned by counter.
Important ! The blanks between the particular characters of the commands only serve the purpose of better
legibility. The input at the PC must be effected without blanks. Control characters (less than 20Hex)
are set in "pointed" brackets. If a false protocol has been sent by the PC, the counter will return an
error message. Please read the paragraph regarding error messages on page 8.