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Page 13
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4
DTS 307 COMMUNICATIONS INTERFACE
SAFETY WARNING
Ensure that
all external devices
that are connected to either or both of the
RS-485 communications bus
, and/or the
digital solid state relay output
have been certified to be
IEC 60950
compliant.
The DTS 307 has 3 options for outputting data
depending on the model ordered
:
•
Modbus RTU over a 2-Wire RS-485 bus
•
BACnet MS/TP over a 2-Wire RS-485 bus
•
A kWh Energy Pulse Output through a Potential-Free Normally Open (N.O.)
Solid State Relay (SSR).
Do NOT use this output to switch more than 50Vdc.
4.1
RS-485 2-Wire Communications
RS-485 is a Daisy Chained Bus terminated at both ends with 120 Ohms.
DO NOT use a STAR or RING configuration.
•
Use 18-22 AWG, 2-core, shielded, twisted pair cable
•
When fitted with
Modbus RTU
, unless otherwise specified through correspondence prior to ordering, the
default Modbus RTU communications parameters are as follows:
o
Modbus Address: 100, Baud Rate: 9600, Parity: None, Data Bits: 8, Stop Bits: 1
(9600, N, 8, 1 #100).
•
Modbus parameters can be changed either through
DTS Config
or by writing to specific registers in the
meter. Please see the
Modbus Map
document or section 7 for
DTS Config
.
•
When fitted with
BACnet MS/TP
, unless otherwise specified through correspondence prior to ordering, the
default BACnet MS/TP communications parameters are as follows:
o
Device Object ID: 473001, MAC Address: 1, Baud Rate: 38400
BACnet MS/TP requires Parity: None, Data Bits: 8, Stop Bits: 1
•
BACnet parameters must be changed via the BACnet interface.
RS-485 2-Wire
+ to +
- to -
S to S