5 flowdde parameter numbers, 6 baud rate setup, 5 basic rs485 operation – Bronkhorst LIQUI-FLOW mini (from 01-07-2013) User Manual
Page 16: 1 hook-up, 1 flow-bus setup, Flowdde parameter numbers, Baud rate setup, Basic rs485 operation, Hook-up, Flow-bus setup
LIQUI-FLOW™ mini
9.17.065
Bronkhorst High-Tech BV
16
3.4.5
FlowDDE parameter numbers
Reading/changing parameter values via FlowDDE offers the user a different and user-friendly interface to the instrument. A DDE-
parameter number is a unique number in a special FlowDDE instruments/parameter database and not the same as the parameter
number from the process on an instrument. Node-address and process number will be translated by FlowDDE to a channel
number.
An instrument parameter can be changed by using the application name: ‘FlowDDE’ with only:
topic, used for channel number: ‘C(X)’
item, used for parameter number: ‘P(Y)’
3.4.6
Baud rate setup
Make sure that the instrument’s baud rate corresponds with the baud rate of the application the instrument is communicating
with. The selectable baud rates are 9K6, 19k2, 38k4, 57k6 and 115k2 Baud.
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For more information regarding communication through an RS232 interface, see document nr. 9.17.027:
RS232 interface with FLOW-BUS for digital instruments.
3.5
Basic RS485 operation
This section is limited to the description of the interface between the LIQUI-FLOW
TM
mini instrument with a master device.
LIQUI-FLOW
TM
mini instruments always serve as slaves in a Modbus system. There is no mutual communication between
Modbus slaves; only between master and slave. The master device is for example a pc.
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More detailed information about Modbus can be found at or any website of the (local)
Modbus organisation of your country (when available).
3.5.1
Hook-up
The illustrations below show examples of LIQUI-FLOW
TM
mini instruments in an RS485 bus-system.
3.5.1.1 FLOW-BUS setup