Hubbell HBLGW04000EUS1, Руководство пользователя, Страница: 53 / 62

Hubbell Ethernet Gateway V4
User’s Manual
PD2864 9/18 Page 52
To add individual registers to a register map:
(1) S
elect the “+” icon from the Register Map
(2) Enter the Register, Expression and Mapping
Modbus Device IDs
Node Maps serve to assign “device IDs” and register maps to specific monitoring nodes. Modbus is
limited to 255 unique device IDs (0-254) per master. To allow more than 255 devices to serve under
one master i.e. Gateways, different nodes can share a device ID but utilize register offset mapping.
Register Offset Node mapping
The Hubbell system supports large numbers of devices reporting through a single gateway. Up to
2000 nodes are supported in the Modbus Enterprise version.
In order to accommodate such large numbers of devices and maintain a simple, common register
map for each node, the Hubbell Modbus interface uses multiple Modbus slave IDs and, if necessary,
register offsets. Automatically assigning different host IDs to each nodes allows each node to have an
identical register map. The number of host IDs is limited to 254 (1-254). For installations larger than
254 nodes register offsets are used.
Each register map is contained within a 200 register window (0-199). The register map, however, can
be offset: the first 254 nodes use host IDs 1-254 with the register window located at address 0
(registers 0-199); the second 254 nodes also use host IDs 1-254, but with the register window located
at address 200 (registers 200-399). This way 2000 nodes can be accommodated with at most 8
register windows using the following mapping:
Nodes Slave IDs Register range
1-254 1-254 0-199
255-508 1-254 200-399
509-762 1-254 400-599
763-1016 1-254 600-799
1017-1270 1-254 800-999
1271-1524 1-254 1000-1199
1525-1778 1-254 1200-1399
1779-2000 1-254 1400-1599
The image on the following page illustrates the mapping process.