Spirax Sarco VLM30 - Page 46

IM-P736-02 EMM Issue 3
46
VLM30 In-Line Vortex Flowmeter
1 Modbus master
2 Terminal resistance
3 Modbus slave 1
4 Modbus slave n to 32
Fig. 30 Modbus network (Example)
Modbus interface
Configuration
Via the Modbus
®
interface in connection with Device Type Manager (DTM).
Transmission
Modbus
®
RTU - RS485 serial connection.
Baud rate
1200, 2400, 4800, 9600 bps
Factory setting: 9600 bps
Parity
None, even, odd
Factory setting: none
Typical response time < 100 milliseconds.
Response delay time
0 to 200 milliseconds.
Factory setting: 50 milliseconds.
Device adress
1 to 247.
Factory setting: 247.
Registered adress offset
One base, Zero base.
Factory setting: One base.
3.19.3 Modbus
®
communication
Using the Modbus protocol allows devices made by different manufacturers to exchange information via
the same communication bus, without the need for any special interface devices to be used. Up to 32
devices can be connected on one Modbus line. The Modbus network can be expanded using repeaters.
2
3
3
4
1