INSTRUCTION MANUAL
FieldLogger
with 128k Memory
0141 0315-57 01. April 2009
B+B Thermo-Technik GmbH | Heinrich-Hertz-Str. 4 | D-78166 Donaueschingen
Technical changes reserved
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FEATURES
Signals supported by RS485 standard. We recommend reading the document “Basic concepts of RS485 and RS422” available in the
CD that is delivered with the equipment.
Communication signals are electrically isolated from the rest of the device, with configurable speed of 1200, 2400, 4800, 9600,
19200 and 57600 bps.
Number of data bits: 8.
Parity: none, odd or even.
Number of stop bits: 1 (odd or even parity) or 2 (no parity).
Response delay: up to 20 ms after command is received.
Protocol: Modbus RTU, available in most supervisory software of the industry.
RS-485 signals are:
D1
D
D+
B
Bidirectional Data Line
Terminal
17
D0
D:
D-
A
Reserved Bidirectional Data
line
Terminal
18
C
Optional Connection that
enhances the Communication
Performance
Terminal
16
GND
PHYSICAL SPECIFICATIONS
•
Three-wire connection (2 data wires and 1 common) between 1 master and up to 247 instruments (maximum of 31 per network
segment) in bus topology.
•
Shielded cable, 3 x 24 AWG (3 x 0,25mm
2
), with shield grounded in one end;
•
16 pF capacitance at every 30 m;
•
Typical impedance: 120 Ohms;
•
Maximum length 1200 m;
USB-i485
R
x- 1
Dat
a l
ogge
r
R
x+ 2
R
T2 3
M
OD4
G
ND 5
6
Tx
-
6
8
Tx
+ 7
7
R
T1 8