Bronkhorst®
Instruction Manual mini CORI-FLOW™ M1x
9.17.050O
24
The communication standards (analog and digital) and fieldbus interface (if applicable) are specified at ordering time, i.e.:
o
In analog mode, the instrument is set to the specified voltage/current range
o
The dedicated fieldbus connection only provides the specified fieldbus interface
Using analog and digital interfaces simultaneously
The instrument can be monitored and operated through the analog and a digital interface simultaneously, but it only
accepts a setpoint from one of both (this is called the control mode; see
for more information). In analog
mode, the analog input and output signals are translated to the digital setpoint and measure parameter respectively. The
default control mode (analog or digital) is determined at ordering time.
3.9.1
Analog operation
With analog operation the following parameters are available:
·
output signal: measured value (voltage or amperage)
·
input signal: setpoint (voltage or amperage; controller only)
·
valve voltage (controller only)
Setpoints below 2% of the full scale will be interpreted as 0%.
3.9.2
Digital RS-232 operation
Digital operation (e.g. via RS-232 or fieldbus) adds extra features to the instrument, such as:
·
Direct reading with a readout/control module or host computer
·
Diagnostics
·
·
Adjustable minimum and maximum alarm limits (
)
·
(Batch) counter (
Make sure in FlowDDE the correct port and baud rate are selected. For RS-232 operation the baud rate must be 38400
Baud.
3.9.2.1
FlowDDE
Digital Bronkhorst® instruments can be operated via RS-232 using the Bronkhorst® FlowDDE server application. Dynamic
Data Exchange (DDE) provides a basic level of inter process communication between Windows applications. Together with a
client application, either self-made or with a third party SCADA program, it is possible to create an easy way of data
exchange between the flow meter/controller and a Windows application. For instance, a cell in a Microsoft Excel
spreadsheet can be linked to the measured value of an instrument; FlowDDE updates the cell automatically when the
measured value changes.
FlowDDE uses specific parameter numbers for communicating with 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. FlowDDE translates the node-address and process number to a channel number.
DDE-client applications communicate with the FlowDDE server by using DDE messages. Before messages can be exchanged,
a DDE link has to be made. A DDE link consists of three parts: the server, the topic and an item. For separation the characters
'|' and '!' may be used, so a DDE link in e.g. Microsoft Excel becomes: Server|Topic!Item.
For standard instrument parameters and the FlowDDE server, these are:
·
Server: FlowDDE or FlowDDE2
·
Topic: ‘C(X)’ for channel number X
·
Item: ‘P(Y)’ for parameter number Y
An example of a DDE link in a Microsoft Excel cell is =FlowDDE|’C(1)’!’P(8)’ to read parameter 8 of channel 1.
