Beijer Electronics SCOM RBC EN - Manual (Page 8)

Device Addressing
8 Beijer Electronics, MAEN993
3 Device Addressing
By default, a Beijer Electronics RBC supports the standard SCOM addressing
scheme, which allows a total count of 16 devices within a network. The address of a
device is set with four DIP switches. If an SCOM command is sent to a device, the
ADR field must contain either the broadcast address 0xFF, or the address of the des-
tination device set by the DIP switches. To eliminate this limit, a new addressing
scheme is supported by the Beijer Electronics RBC.
According to the previous chapter, the width of the ADR field is 1 byte (or 8 bits).
The standard SCOM addressing scheme uses only the lower 4 bits of this field (only
in case of the broadcast address, all bits are used), allowing a maximum of 16 address-
es.
The new addressing scheme, implemented in Beijer Electronics RBC, uses also the 4
upper bits. To distinguish between the standard and new addressing scheme, these
bits are called “group bits” or simply “group”. Based on this definition, the following
table shows field ADR in more detail:
As shown in the table, a group between 0 and 14 can be specified. Group 15 is not
supported, to avoid address collision with the broadcast address. Thus, together with
the address field, a total count of 15 x 16 = 240 devices can be connected to one net-
work.
Grouping of devices is activated only, if the devices are set up to use the software con-
figured address, instead of the hardware address specified by the DIP switches. If the
device uses the hardware address, the group address is automatically set to 0, regard-
less of the group configuration.
Beijer Electronics RBC addresses are always given in a dotted notation as “group.ad-
dress”. This means, if a device belongs to group 7 and its address is 3, the resulting
address will be 7.3, which is 115 (0x73). In the standard mode (i.e. DIP switch ad-
dress is used), the device address will be 0.3 (or simply 3) for the given example, be-
cause the group bits are set to 0.
If a Beijer Electronics RBC is configured as remote controller (default), it addresses
all reachable devices by sending a broadcast command.
Related information
Message Format and Description
ADR bits 15...8 ADR bits 7...0
Group
(0 … 14) Address
(0 … 15)