Bronkhorst®
Instruction Manual ES-FLOW™ 1xxC
9.17.153A
24
FLOW-BUS
Within the FLOW-BUS protocol (ProPar when using RS-232 communication), parameters are identified by a unique
combination of a process number and a parameter number:
[Pro]
Process number
[Par]
Parameter number
For more detailed information, consult the RS-232 manual (see
).
Modbus
In the Modbus protocol, parameters are accessed by specifying their unique decimal register number or corresponding PDU
address (Protocol Data Unit). The PDU address is the hexadecimal translation of the register number minus 1, e.g. register
number 1 corresponds to PDU address 0x0000, register number 11 corresponds to PDU address 0x000A:
[address]
Hexadecimal PDU address
[register]
Decimal register number
Modbus address blocks are two bytes big. Larger data types use up to 8 subsequent address blocks, resulting in a
maximum variable length of 16 bytes. Values longer than the maximum length are truncated.
For more detailed information, consult the Modbus manual (see
).
Other interface protocols
Parameter descriptions in this document are based on their availability with FLOW-BUS, Modbus or RS-232 (ProPar)
communication. Due to limitations in, for example, memory capacity or communication properties, definition files for other
fieldbus systems usually do not make all parameters available.
For information about parameter access and availability for Bronkhorst® instruments in a specific fieldbus network,
.
6.1.1
Measurement and control
Measure
Type
Access
Range
FlowDDE
FLOW-BUS
Modbus
Unsigned int
R
0…41942
(65535*)
8
1/0
0x0020/33
This parameter indicates the flow metered by the instrument. The value of 32000 corresponds to 100%, the maximum
measured value output is 131.07%, which translates to 41942.
*In case the instrument is prepared for bi-directional measurement, the negative signals with an output range of -
73.73…-0.003% are represented by the range of 41943…65535, whereas the positive signals 0…131.07% are still
represented by the range of 0…41942. (FlowDDE converts the numbers to negative values automatically).
Setpoint
Type
Access
Range
FlowDDE
FLOW-BUS
Modbus
Unsigned int
RW
0…32000
9
1/1
0x0021/34
This parameter is used to set the required flow rate for the controller. The signals have the same range as
Measure
, but the
setpoint range is limited between 0 and 100% (0…32000).
6.1.1.1
Advanced measurement and control
Fmeasure
Type
Access
Range
FlowDDE
FLOW-BUS
Modbus
Float
R
-3.4E+38…
3.4E+38
205
33/0
0xA100…0xA101/ 41217…41218
Floating point variant of
Measure
.
Fmeasure
shows the measured value in the capacity unit for which the instrument is set.
The instrument uses parameters
Capacity
,
Capacity 0%
,
Capacity Unit
and
Sensor Type
to calculate
Fmeasure
.
