AMG Systems Ltd. reserves the right to make changes to this document without
notice. The information herein is believed to be accurate. No responsibility is
assumed by AMG for its use.
Page 4 of 5
AMG2743-SF Instruction
Sheet D15332-00
Mounting Details
The unit is designed to mount into a panel via the four mounting slots of 4.5mm x 10mm.
Configuration of the RS422/485 Data Channel
The RS422/485 data channel can operate in two modes that are set by SW2 on the main PCB. (See
below for
removal of the PCB
and access to SW2)
Mode 1 –
RS485 two wire half duplex transmission.
Mode 2 –
RS422 four wire full duplex transmission. In this mode the RS422 output will transmit a
tristate condition as well as logic high and logic low for systems which require bus-ing of
the RS422 four-wire connection.
MODE
Configuration Details
SW2
position 1
SW2
position 2
SW2
position 3
SW2
position 4
1
RS-422 4 wire Point-to-Point -
and RS-422 BUS system
OFF OFF OFF OFF
2
RS-485 2 wire BUS systems
OFF
ON
ON
ON
The data input for both the RS485 and the RS422 modes detects a tri-state input condition by
monitoring the differential voltage level across the input. A differential level below 500mV positive or
negative will be detected as a tristate condition. A level above 500mV positive or negative will be
detected as a logic 1 or logic zero respectively.
It is important therefore to terminate the RS485
bus or the RS422 input bus using 120ohms if a pre-bias is present on the RS485 or RS422 bus.
A large number
of
third party equipment manufacturers apply a pre-bias on their RS485 bus. This pre-
bias is applied by pulling one arm of the RS485 bus high (+5 volts) and the other arm low (0 volts)
using high value resistors within the third party equipment. In order to ensure that a tri-state condition
is detected by the AMG2700 equipment, then these resistors should have a value above 1kohm.
SW1 Switch Settings
All SW1 switch settings are set at the factory as follows:
Switch
Position
Description
Setting
1 Video
channel
configuration
OFF
2 Video
channel
configuration
OFF
3 Video
channel
configuration
OFF
4
Primary / Secondary Board Setting
ON
5
Dual Redundant / Not dual redundant
OFF
6 Not
Used
OFF
7 Not
Used
OFF
8
On board data / Separate data card
ON
9
RS232 or RS422/485
OFF for
RS485/422
10
RS232 or RS422/485
OFF for
RS485/422
Removal From the Case
Note: -
The 2700 PCB’s are static sensitive. Handle with proper care and use normal electrostatic
discharge (ESD) procedures. Use properly grounded protection (for example, wrist stamps) when
handling the PCB.
In order to remove the case (to access SW1 and SW2)
