System Bus; Bus Address; Part-Setting And Partitioned Modes; Part-Setting Mode - Scantronic i-on Series Installation Manual

Introduction

System bus

All control units except the i-on Compact have a system bus to connect devices such as
wired keypads, expanders, remote power supplies and base stations (for KEY-RKPZ
keypads). The i-onG3MM has two busses. The bus architecture allows the system to be
easily expanded to accommodate additional devices if the need arises.
Devices can connect to a bus using a "daisy chain" or star layout, as shown in Figure 1.
Figure 1. Daisy chain and star connections

Bus address

Each device has a unique bus address. A device obtains its address from the control unit
either during the commissioning stage of a new installation, or when the installer adds the
device from the Installer menu. The control unit assigns the lowest-available address.
Each device stores its address in non-volatile memory.
For the i-onG3MM, the address is unique across both busses, so unlike previous-
generation i-on systems, the same address does not exist in both busses. The system As
an installer, you have complete flexibility to add a device to either bus. A benefit of the two-
bus i-onG3MM is that if there is a cable fault on one bus, it does not affect the other bus.

Part-setting and partitioned modes

All control units except i-on Compact offer part-setting and partitioned modes. The i-on
Compact offers part-setting mode only.

Part-setting mode

In part-setting mode, the control unit can set in one of four ways: either full set or one of
three part sets (part set B, C or D). Each zone can belong to one or more part sets (using
the Part Set attribute). When the system is full set, the control unit sets all zones,
irrespective of the part set they belong to. When part set, the control unit sets only those
zones that belong to the part set.
In a part-setting system, the control unit responds to just one keypad at a time.
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