Filter
Top Products
58
Service Manual
Third edition, June 1997
Half duplex two-wire transmission - S1-S4:1-2.
Full duplex four wire transmission - S1-S4:2-3.
The connection of the Level Unit and LevelDatic system
requires half duplex, while the Tank Display Units require
full duplex.
Note: When trouble shooting you might need to exchange two RS
485 Interface Boards. Remember to check the setting of the jumpers
for correct transmission. A 485-bus for a LevelDatic system with
more than one module may use an unterminated board depending
upon its location.
The Interface Board has a green LED for indication of re-
ceived signals and a yellow LED for transmitted signals. All
the received signals are transmitted back on the channel and
it is therefore quite difficult to use these LEDs to see if any
answers are transmitted.
4.4 SIOX Interface Board
The SIOX Interface Board is used to connect the optional
SIOX field bus system to the I/O Box. It converts the signal
between RS-232 and the SIOX field bus. If an external power
supply is used, it also provides galvanic isolation.
The SIOX field bus is a two wire current loop bus which is
either powered from the motherboard or from an external
power supply. Jumpers S1 and S2 must be set according to
the power connection.
The Interface Board has a green LED for data, which is nor-
mally lit. A ground failure will blow the fuse (F1) and light
the red LED on the board.
Each SIOX module also has two LEDs. The Live Bus-LED
indicates that there is communication on the bus. The An-
swer-LED flashes when the module is sending an answer
onto the bus. If the Answer-LED does not flash, the SIOX
module might need to be replaced.
4.5 PRS Interface Board
The PRS Interface Board functions as a modem. It transform
the digital signals to audio signals. Its transmission speed is
1200 Baud. The PRS Interface Board has a green LED for
indication of received signals and a yellow LED for transmit-
ted signals.