HW Group Poseidon 2250, Краткое руководство

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Poseidon 2250 – Short Manual HW group
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Termination
The RS-485 bus must be terminated at its end. The following options are available:
Internal jumper on certain sensors (jumper named TERM or TERMINATOR) – for example
Temp-485 or HTemp-485
B-Cable adaptor with “LAST” configuration selected using the switches
External resistor to terminate the bus at the “last” sensor, if the sensor has no jumpers or
DIP switches (Temp-485-Pt100). Connect the resistor between the A and B terminals of the
last sensor.
The resistance of this resistor should be 120Ω, For short wirings, 470Ω can be used to
reduce the current consumption of the sensors.
Note: A disadvantage is that it is necessary to have a wiring topology with a single
beginning and a single terminated end , as opposed to the popular star topology with
a single interconnection point.
Special accessories for the RS-485 bus
B-Cable - RJ45 / 4-wire connection
The B-Cable module is an adapter that converts a RJ45 jack
connection to a block of 4 terminals
A,B,+,– .
Some of the available RS-485 sensors already have a RJ45
jack; however, some only have 4 terminals labeled
A,B,+,- .
Such sensors can be connected to the Poseidon 1250 unit or to
an S-Hub using either a TP cable (4 or 6 wires) or the B-Cable
module.
The 4-wire connection
length should not exceed
20cm.
Sensor position on the RS-
485 bus (MIDDLE / LAST)
is selected with jumpers;
see the picture for details.