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Magic 485F Adapter

2.4 Configurable Options

Selection of DCE or DTE (485F25 only)

The unit, as supplied from the factory, is configured to interface directly to a DTE i.e. a PC or
dumb terminal . In the majority of applications this will be correct. This is set by the Jumpers J1
to J2. If required the unit can be converted to connect to a DCE e.g. a moedm, by the
repositioning of J1 and J2, as detailed below.

Link

Function

J1 1-2 & J2 1-2

RS232 connector wired as PC serial port (default factory setting)

J1,1- J2,1 & J1,2 - J2,2

RS232 connector wired as Modem serial port

Selection of Local Echo On/Off in Half Duplex Operation

The factory default configuration of link (J3) fitted causes the transmitted data to be echoed to
the receiver in half duplex operation. If this echo is not required, the link can be removed.

For full duplex operation, the link J3 must be in its default condition for the receiver to be
continuously enabled. Echo back is not appropriate to full duplex operation.

Link
485F25

485F9

Function

J3 1-2

J3 linked

RS485 local echo disabled (default factory setting)

J3 2-3

J3 cut

RS485 local echo enabled, transmitted character echoed back to

receiver

Transmission Line Termination

For proper operation of the RS422/485 bus in full or half duplex, multi-drop or point-to-point
communication, it is recommended that termination be applied to the receiver end of the data
lines. The simplest form of termination is line-to-line with typically a 120 

 resistor across the

differential input.

In a multi-drop system, the terminator resistor is only required at the device receiver located at
the far end of the cable. If this is in half duplex operation, then both ends of the bus cable are
equipped with receivers (transceivers) so termination is necessary at both ends. Although the
Magic 485F Adapter will drive loads as low as 27 

, in general, RS485 transmitter circuits are

specified as being capable of driving a minimum load resistance of 60 

, so no more than two

terminator resistors should be connected to any one bus.

The Magic 485F Adapter is equipped with a terminator resistor for the receiver input pair. This
resistor is connected into circuit by the setting of switch SW1 Bit 4 on the 485F25 or solder link
J1 on the 485F9. Factory default settings are with the receiver input termination in circuit (SW1-
4, on) for the 485F25, and (J1 solder link tracked) for the 485F9. It can be removed from the
circuit by setting SW1-4 to off on the 485F25 or cutting the fine track connecting the pads of J1
on the 485F9.

Содержание Magic 485F25

Страница 1: ...oduct in a proper and efficient manner The information contained has been reviewed and is believed to be accurate and reliable however Amplicon Liveline Limited accepts no responsibility for any problems caused by errors or omissions Specifications and instructions are subject to change without notice Magic 485F Instruction Manual Part Nº 859 933 74 Issue A3 Amplicon Liveline Limited Prepared by J...

Страница 2: ...clare that the product s described in this Instruction Manual perform in conformity with the following standards or standardisation documents Electro Magnetic Compatibility EMC EN55022 1995 Emission Standard BS EN50082 1 1992 Generic Immunity Standard EMC Directive 89 336 EMC Jim Hicks I Eng FIEIE Managing Director Amplicon Liveline Limited ...

Страница 3: ...signals are connected through a pluggable 8 way screw terminal assembly at the free end of the Adapter 1 2 The Products Described in this Manual The 485F range of boards share some common circuitry and features and are referred to in this manual either generically or individually 485F Refers to both boards 485F25 Refers to the 25 way D type version only 485F9 Refers to the 9 way D type version onl...

Страница 4: ...the information in this manual to ensure that the product is being correctly applied If an application problem persists please request Technical Support on one of the following numbers Telephone UK 01273 608 331 International 44 1273 608 331 Fax UK 01273 570 215 International 44 1273 570 215 E mail support amplicon co uk Internet www amplicon co uk 1 5 Repairs If the Magic 485F Adapter requires re...

Страница 5: ...number on the outside of the packaging to ensure that the package is accepted by the Goods Inwards Department Address repairs to Customer Services Department AMPLICON LIVELINE LIMITED Centenary Industrial Estate Brighton East Sussex BN2 4AW England ...

Страница 6: ...rough a pluggable 8 way screw terminal connector assembly at the free end RS422 485 Connections on 8 way Pluggable Terminal Strip The DC power input RS485 transmission turnaround external control signal and RS422 485 data signal connections are made via an eight way screw terminal connector The supplied connector can be unplugged from the Adapter for ease of making the cables without removing the ...

Страница 7: ...or convenience the plastic case is supplied in two parts and should only be clipped together when any configuration changes have been made Operational tests can be performed before the case is fitted FIGURE 2 1 485F25 BOARD LAYOUT AND JUMPER POSITIONS FIGURE 2 2 485F9 BOARD LAYOUT AND LINK POSITIONS SK2 PL1 J2 C2 U1 C3 U4 U5 C6 R5 C2 U3 C1 R6 J3 C7 R4 R3 R2 C5 C4 R1 D1 J1 ...

Страница 8: ...er Transmission Line Termination For proper operation of the RS422 485 bus in full or half duplex multi drop or point to point communication it is recommended that termination be applied to the receiver end of the data lines The simplest form of termination is line to line with typically a 120 Ω resistor across the differential input In a multi drop system the terminator resistor is only required ...

Страница 9: ...ed OFF OFF OFF X RS485 transmitter turnaround time 4 us ON OFF OFF X RS485 transmitter turnaround time 8 us OFF ON OFF X RS485 transmitter turnaround time 16 us ON ON OFF X RS485 transmitter turnaround time 32 us OFF OFF ON X RS485 transmitter turnaround time 64 us ON OFF ON X RS485 transmitter turnaround time 128 us OFF ON ON X RS485 transmitter turnaround time 256 us ON ON ON X RS485 transmitter...

Страница 10: ...s supply voltage must be 230 VAC 10 50 Hz The DC output is by a two wire cable approximately 2 m in length This cable is terminated in a moulded connector which must be cut off and discarded The two wires can then be parted and stripped back about 6 mm The black wire is negative and goes to terminal 8 GND of the Magic 485F Adapter and the black wire with a white stripe is positive and goes to term...

Страница 11: ...ut Resistance 5 kΩ RS232 High signal output 9 V RS232 Low signal output 9 V RS232 Output Resistance 300 Ω RS422 485 Input sensitivity 0 2 V RS422 485 Input Hysteresis 70 mV RS422 485 Output drive 1 5 V minimum fully loaded RS422 485 Output load 27 Ω minimum RS422 485 Receiver I P Termination 120 Ω resistor across differential input terminals Can be disconnected by switching SW1 4 Data Rate 120 kBd...

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