
FT 80 RLA Distance sensor - 068-13715 - 04.05.2009-03
Mounting and
operating instructions
40
Sensor configuration with the ProgSensor software
The operating software “ProgSensor” is available to facilitate programming of versions S1. Its simulation mode
indicates the correct bus commands for the respective case.
For more information see our homepage: www.sensopart.de and the order information on
Transmission protocol
Transmission frame
The bus-compatible RS 485 interface of FT 80 RLA version S1 operates in half-duplex mode (1 Stopbit, no parity).
As a rule, the FT 80 RLA-S1 sensor is a slave and only sends data when addressed by a higher ranking control
system (master) except difference measuring.
A baudrate of 38,4 KBaud and the following protocol must be observed for data transmission:
• 1 selection bit (MSB) + 7 data / address bit
MSB
6 ..... 1 LSB
address bit
7 data / address bits
Procedure:
When the address bit has been set, the FT 80 RLA-S1 sensor compares the bus address with its own. If they match,
the FT 80 RLA-S1 sensor interprets all further data and sends an appropriate feedback signal.
The structure of the transmission frame is as follows:
1st byte
2nd byte
3
rd byte
4th Byte...(n-1).Byte
Last byte
Request from master
Address of slave
Length
Command
Parameter(s)
Checksum
Answer from slave
Address of slave
Length
Command
Parameter(s)
Checksum
Slave answers:
Address of slave *
1
4
N
Checksum
Address of slave *
2
4
Y
Checksum
Address of slave *
3
4 + n
Y
1
st
parameter, 2
nd
parameter,
3
rd
parameter, …, n parameter
Checksum
Length =
Number of characters incl. checksum and address byte
Command = See table of bus commands on page 41
Parameters = Parameter byte 0 to n, depending on command. The slave sends the requested data
in this range.
Checksum = Exclusive OR of all characters sent incl. address byte
N*
1
is sent when an error in checksum or framelength or an unknown / unvalid parameter or command occurs.
N*
2
is sent when the command has been carried out.
N*
3
is sent when parameters have been queried.