Bronkhorst EL-FLOW Base 2014 - Manual (Page 12)

BRONKHORST HIGH-TECH
2.8 Electrical connections
2.8.1 Interface
EL-FLOW Base instruments can be operated by means of:
1. Analog interface (0...5Vdc or 0...10Vdc or 0...20mA or 4...20mA)
2. RS232 interface with FLOW-BUS protocol
3. RS485 interface with Modbus protocol
All above operation options are standard available in EL-FLOW Base instruments.
According to the pin-designation both RS232 and RS485 are assigned to the same pins. When connecting
these pins to either of the two, the instrument will automatically detect which protocol to use. When
sending a frequent request to the instrument, it will be capable of recognising the protocol,
once the instrument detect this protocol, it will send an answer.
The instrument will remember the detected protocol as long as the instrument is powered. This auto
detection can not be switched off or by-passed.
For electrical hook-up diagrams refer to document 9.16.091, “Hook-up EL-FLOW Base”
This documents can be found at:
http://www.bronkhorst.com/en/downloads
2.8.2 Power Supply
EL-FLOW Base controllers are powered with +15 Vdc to +24 Vdc.
When providing your own power supply be sure that voltage and current rating are according to the
specifications of the instrument(s) and furthermore that the source is capable of delivering enough
power to the instrument(s). Refer to Hookup EL-FLOW Base, document nr. 9.16.091, for more details.
Bronkhorst High-Tech B.V. recommends the use of their standard cables. These cables have the right
connectors and if loose ends are used, these will be marked to prevent wrong connection.
When using other cables, cable wire diameters should be sufficient to carry the supply current and
voltage losses must be kept as low as possible. When in doubt: contact your distributor.
EL-FLOW Base instruments carry the CE-mark. Therefore they have to comply with the EMC
requirements as are valid for these instruments. However compliance with the EMC requirements is not
possible without the use of proper cables and connector/gland assemblies.
!
When connecting the system to other devices (e.g. to PLC), be sure that the integrity of the shielding is
not affected. Do not use unshielded wire terminals.
2.9 Power and warm-up
Before switching on power, check if all connections have been made according to the hook-up diagram.
It is recommended to turn on power before applying pressure on the instrument and to switch off
power after removing pressure.Check fluid connections and make sure there is no leakage. If needed
purge the system with a proper fluid. Only purging with gases is allowed. Turn on power and allow at
least 30 minutes warming up and stabilizing. During warm-up period, fluid pressure may either be on or
off.
2.10 Pressure supply / Start-up
When applying pressure to the system, take care to avoid pressure shocks in the system and increase
pressure gradually up to the level of the actual operating conditions.
Page 12 EL-FLOW Base Series Mass Flow Controllers 9.17.061