SERVICE
19
MAGNET POWER SUPPLY SYSTEM 8500
3.3.2.
Data communication.
Connection for the host is located on the Control Board behind the front door of the Power Supply.
The host connection cable can get access to the board through the front-hole in the bottom of the
power supply.
The pin numbers on the D-SUB Female 25 - pin connector tell which type of communication is used.
RS 232C, RS 422 or RS 485.
The direction used in the tables below are:
Rx : Signals received by the Control Module from its host.
Tx : Signals transmitted by the Control Module to its host.
RS 232C DB 25 S.
RS 422 DB 25 S.
RS 485 DB 25 S.
Pin No. Signal.
Pin No.
Signal
Pin No.
Signal
2
Tx.
7
GND.
7
GND.
3
Rx.
9
Tx high.
9
Tx/Rx high.
7
RETURN.
10
Tx low.
10
Tx/Rx low.
11
Rx high.
12
Rx low.
NOTE! The selection between RS 232, RS 422 and RS 485 is done with jumpers on the Control
Board.
Local line: Jumper
RS232:
Jumper on ST16
ST14 and ST15 must be left open
RS422
Jumper on ST15
ST14 and ST16 must be left open
RS485
Jumper on ST14
ST15 and ST16 must be left open
RS485
Jumper on ST13
ST19 must be left open
Remote line:
RS232:
Jumper on ST9
ST10 and ST11 must be left open
RS422
Jumper on ST10
ST9 and ST11 must be left open
RS485
Jumper on ST11
ST9 and ST10 must be left open
RS485
Jumper on ST18
ST17 must be left open
3.3.2.1. Termination using RS 422 or RS 485.
There is no termination resistor mounted inside the control module. An external termination resistor
of 100 Ohm must therefore be added at the end of the communication cable. This for both the local
and the remote line.
Hint. This resistor can be placed inside the last DB 25 plug for the remote line and the DB9 plug
for the Local line.
When using the RS 485 or the RS 422 line in the multi drop configuration, it is very important during
an address transfer to leave the lines at the "SPACE" state when tri stated. That is when the line is
not driven by any transmitters at all. The "SPACE" state can be utilized by adding 1K Ohm resistors
to +5V(non inverting) and GND (inverting) on both the transmit and the receive lines. The control
module can provide this by short circuiting ST2, ST4, ST6 and ST8 for the remote line and ST1,
ST3, ST5 and ST7 for the local line (use a thin soldering iron). The 1K resistors increases the noise
DANFYSIK A/S - DK 2630 TAASTRUP - DENMARK.
DOC NO P80303Sk
