Rs 485 Multi-Drop Mode; Rs485 Multi-Drop Mode Installation Procedure - Elster A1140 User Manual

10
A1120/40 Users Manual - Chapter 3
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A1120/40
Two-way adaptor
Tx
2
Rx
3
No Connection
4
Zero Volts
5
4.2

RS 485 Multi-drop Mode

A1120/40 meters allow up to 32 meters to be connected in multi-drop configuration.
This configuration allows transmission over longer distances of up to 1.2km.
Each meter in the chain will require an Amplicon line driver to convert RS232 communications
to RS485. The first meter in the chain will require a two-way RJ11 adaptor.
4.2.1

RS485 Multi-drop Mode Installation Procedure

The Figures below show the RS485 multi-drop connections.
1. Observe all Safety Warnings, Warnings, Precautions for handling electrostatic
discharge sensitive devices and EMC Guidelines in Section 2
2. Remove the terminal cover of the first A1120/40 meter in the multi-drop chain
3. Check that the terminal cover plate is in place. If the terminal cover plate is not in place,
switch off all supplies to the meter
4. Connect a two-way RJ11 adaptor to the RJ11 port of the first meter in the multi-drop chain
5. Connect the modem to the first port of the adaptor
6. Using a suitable lead, connect the D type of the Amplicon line driver to the RJ11 of the first
meter in the chain
7. Wire pins 1-8 of the first line driver to pins 1-8 of the line driver of the second meter in the
multi-drop chain.
8. At this point, communications with the meter be can checked by sending an appropriate
scheme to the meter
9. Replace the terminal cover and fit appropriate seals
10. Follow steps 6 to 9 to connect the next meter in the chain
11. Replace the terminal cover and fit appropriate seals
12. Continue to the next meter
© Elster Metering Limited - M181 001 4A - 5/2007 DRAFT
A1120/40
Two-way adaptor
Rx
2
Tx
3
4
5