Bronkhorst®
Instruction Manual EL-FLOW® Select
9.17.099J
34
4
Digital parameters
This section describes the most commonly used parameters for digital operation of the EL-FLOW® Select. Descriptions are
grouped by category in tables as shown below:
Type
Access
Range
FlowDDE
FLOW-BUS
Modbus
[type]
RW
B
[x]…[y]
[DDE par]
[Pro]/[Par]
[address]/[register]
In this manual, parameter names are printed in italics (reverted to
normal
where embedded in italics, like in this tip).
Type
Unsigned char
1 byte unsigned integer (0…255)
Unsigned int
2 byte unsigned integer, MSB first (0…65535)
Unsigned long
4 byte unsigned integer, MSB first (0…4294967295)
Float
4 byte floating point, IEEE 32-bit single precision, MSB first
Unsigned char [x] x byte text string
Access
R
Parameter value can be read
W
Parameter value can be written
B
Parameter is secured and only accepts values if parameter
Init Reset
is set to 'unlocked' first
Range
Some parameters only accept values within a certain range:
[x]
Minimum value
[y]
Maximum value
FlowDDE
Parameter number within FlowDDE
FLOW-BUS
FLOW-BUS uses the ProPar protocol, where parameters are identified by a unique combination of a process number and a
parameter number:
[Pro]
Process number
[Par]
Parameter number
·
For more information about setting up a FLOW-BUS network with Bronkhorst® instruments, consult the FLOW-BUS
manual (see
).
·
For more detailed information on the ProPar protocol, 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 about setting up a Modbus network with Bronkhorst® instruments, 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.
Not all parameters described in this document are necessarily available with all digital interface types. For information
about parameter access and availability for Bronkhorst® instruments in a specific fieldbus network, consult the according
