Bronkhorst IQ+FLOW (till 01-07-2013) - Manual (Page 18)

9.17.045 page 18
3.6 Basic parameters and properties
3.6.1 Introduction
Most instrument parameters can only be accessed with digital communication. For each communication protocol the
instrument parameters are accessed differently. When using Bronkhorst® software programs FlowView or FlowPlot,
easy access is provided to the mostly used parameters by menu interfaces. When using other communication methods
the addressing method for the supported communication protocol is presented for a number of basic parameters in a
table as seen below:
Type Access Range FlowDDE FLOW-BUS Modbus
[type] RW  [x]…[y] [FB] [Pro]/[Par] [address]/[index]
Type
Unsigned char 1 byte character
Unsigned char[x] x byte array (string)
Unsigned int 2 byte unsigned integer
Unsigned long 4 byte unsigned long
Float 4 byte floating point
Access
R The parameter is read-only
RW The parameter can be read and written
RW The parameter is protected and can only be written when the ‘Init Reset’ parameter is set
to 64. See section 4.1.1 for more details.
Range
Some parameters only accept values within a certain range:
[x] Minimal value of the range.
[y] Maximal value of the range.
FlowDDE
Parameter number within FlowDDE. Refer to section 3.4 for more information about FlowDDE.
FLOW-BUS
Within the FLOW-BUS protocol (Propar when using RS232) parameters are divided into a ‘Process’ and a ‘Parameter’
number. To address parameters using the FLOW-BUS/Propar protocol write both numbers:
[Pro] Process number
[Par] Parameter number
Check document 9.17.027, “RS232 interface with FLOW-BUS protocol” for detailed information.
Modbus
Parameters can be read or written via the Modbus protocol by specifying either the PDU Address or the register
number. The PDU Address is a hexadecimal number (identifyable by the ‘0x’ prefix), which corresponds to the decimal
register number minus one, e.g. PDU Adress 0x0000 equals register number 1, PDU Adress 0x000A equals register
number 11 etc.):
[address] Hexadecimal PDU address
[index] Decimal register number
For the Modbus protocol every two bytes are addressed separately.