Bronkhorst EL-FLOW Prestige - Manual (Page 42)

Bronkhorst High-Tech B.V.
EL-FLOW Prestige 9.17.084 42
4.3 Field bus operation
4.3.1 FLOW-BUS master/slave controller operation
EL-FLOW Prestige instruments offer possibilities for master/slave control via FLOW-BUS. The output value of any instrument
connected to FLOW-BUS is automatically available to all other instruments (without extra wiring). To setup master/slave control the
‘ 12 Control Mode’ of the instrument can be set to ‘FLOW-BUS Slave’ (value 2) or to ‘FLOW-BUS Analog Slave’ (value 13), depending
on how the ‘ 139 Slave Factor’ should be set. Via the parameter ‘ 158 Master Node’ the master device for the instrument is set. It is
possible to have multiple masters and slaves in a FLOW-BUS system. A slave instrument can also be a master for other instruments.
Setpoints from master instruments can be received via FLOW-BUS only. The parameters for master/slave control can
be changed through both RS232 and FLOW-BUS.
Master Node
Type Access Range FlowDDE FLOW-BUS Modbus
Unsigned char RW 1…125 158 33/14 0x042E/1071
Set the master node for the instrument.
Slave Factor
Type Access Range FlowDDE FLOW-BUS Modbus
Float RW 0…500 139 33/1 0x0421/1058
The controller output from the master instrument is multiplied by the ‘ 139 Slave Factor’/100% to get the slave instrument setpoint.
Example: if a master output is 80% and the ‘ 139 Slave Factor’ value = 50, then the slave instrument setpoint is 80% x 50%/100% =
40%.
4.3.2 Changing baud rate, node address and parity
Any changes made to the instrument communication settings will not be restored after a factory reset. See section
5.2 for more details.
Top connector communication
Change the node address of the instrument by using the instructions for the applicable field bus in chapter 3. Change the baud rate
or parity of the installed field bus (top connector) with the following parameters using the RS232 interface:
Fieldbus 1 baudrate
Type Access Range FlowDDE FLOW
-BUS
Modbus
Unsigned long RW 0…10000000000 201 125/9 0xFD48...0xFD49/64841...64842
For the accepted values see the applicable field bus in chapter 3.
Fieldbus 1 parity
Type Access Range FlowDDE FLOW-BUS Modbus
Unsigned char RW 0…2 335 125/12 0x0FAC/4013
The following values are accepted:
0 – no parity
1 – odd parity
2 – even parity