Model 485HF9
Page 4
1. INTRODUCTION
1.1
General Description
The Model 485HF9 Adaptor is a compact, plug-in unit providing bi-directional conversion of
serial data communications signals between the following standards:-
The Model 485HF9 Adaptor is equipped with a 9 way, female D type connector. Many RS-232
devices are similarly equipped, and when properly configured and powered, the adaptor can be
plugged into the appropriate port to convert the transmit and receive signals to RS-422/485
levels. RS-232 hardware handshaking lines are looped back, and the RS-232 Request To Send
(RTS) control line can be used for RS-485 transmission turnaround if required. The unit is
supplied for the RS-232 host device configured as Data Terminal Equipment (DTE).
The data conversion process changes only electrical levels, and the pin-out configuration is in
accordance with the appropriate standards. The adaptor itself is not considered as DTE or
DCE, and where these terms are used, they apply to the RS-232 equipment to which the Model
485HF9 Adaptor is connected.
RS-485 multi-drop operation allows up to 32 devices to be connected in a simple network on a
single serial bus. The transmitter has a tri-state output and may be disabled to allow reception
over the same wire pair. The high impedance state (transmitter disabled) is commanded from
an external control signal or from the host computer RTS line.
DC power for the Model 485HF9 Adaptor must be applied from an external source. The DC
power lines plus the RS-422/485 data and control signals are connected through a pluggable 8
way screw terminal assembly at the free end of the Adaptor.
EMC Considerations
In order to maintain compliance with the EMC directive, 89/336/EEC, it is mandatory that the
final system integrator uses good quality screened cables for external connections. It is up to
the final system integrator to ensure that compliance with the Directive is maintained. Amplicon
Liveline offers a series of good quality screened cables for this purpose. Please contact our
sales staff.
1.2
Technical Features
•
RS-422 or RS-485 compatible
•
Multi-drop capability
•
Plugs directly into standard 9 pin male connector
•
Configured for operation with DTE host
•
Single power supply connection. Polarity protected
•
Remote connections via pluggable terminal strip
•
Compact and versatile
RS-232
RS-422
OR
RS-232
RS-485
Summary of Contents for 485HF9
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