Flintec LDU 68.2 - Manual (Page 7)

LDU 68.1 & 68.2 Technical Manual, Rev. 12 January 2010 Page 7 of 28
4. Communications and Getting started
4.1. Serial Interface
Communicating with the LDU 68.1 digitizer is carried out via the RS422/RS485 port.
The data format is the familiar 8/N/1 structure (8 data bits, no parity, 1 stop bit).
Available baud rates via the RS422/RS485 port are as follows: 9 600, 19 200, 38 400, 57 600 or 115 200 baud.
RS422:
 Connection using a 4 wire technique
 Point-to-Point connection, i.e. no bus communication possible
 Half duplex setup (DX=0)
RS485:
 Connection using 2- or 4-wire techniques
 Multi-drop connection possible, up to 32 LDU XX.X
 Half or Full Duplex (DX=0 or DX=1) possible
(RS232):
 The optional adapter board UA 77.1 is available which has an RS485/RS232 converter built in.
4.2. Command Language
The command set of LDU XX.X series is based on a simple ASCII format (2 capital letters). This enables the
user to setup the device, get results or check parameters.
Example: LDU XX.X with the address or channel number 1 is connected via the RS 485 port to a bus system.
You want to get the net weight.
In this manual means: Space “_“ and Enter (CR/LF) ““
Master (PC / SPS) sends Slave (LDU XX.X) responds Meaning
OP 1
 Open device #1
OK Device # 1 ready
GN  Get net weight
N+123.45 Net weight with algebraic sign / floating point
The command OP_2 opens the communication channel to LDU XX.X device #2. Now device #2 acknowledges
that it is active and responds to any commands on the bus. Communication with device #2 will be closed by
another OP command (for another device on the bus e.g. OP_5) or by the command CL_2.
Each OP_X command implies a CL command to all other devices on the bus except device #X. This makes the
address structures easier and the system performance improves.