BRONKHORST®
9.17.061
EL-FLOW
Base
Series Mass Flow Controllers
Page 15
3
Basic Operation
3.1 General
An EL-FLOW
base
instrument can be operated by means of:
Analog interface (0...5Vdc/0...10Vdc/0...20mA/4...20mA)
Digital RS232 Flowbus interface (connected to COM-port by means of special cable on 38400 Baud)
Digital RS485 Modbus interface.
Operation via analog or digital interface can be performed at the same time. A special parameter called
“control mode” indicates to which setpoint the controller should respond.
3.2 Analog operation
At analog operation following signals are available:
measured value (analog output)
setpoint (analog input)
The type of installed analog interface (0-5V, 0-10V, 0-20mA or 4-20mA) can be found in the model key of
the instrument. Refer to paragraph 1.6.2.
Setpoints below 2% of the full scale will be interpreted as 0% setpoint.
When operating the instrument through the analog interface it is possible to connect the instrument
simultaneously to RS232 or Modbus/RS485 for reading/changing parameters (e.g. controller response
or other fluid selection).
