Bronkhorst RS232 interface - Manual (Page 28)

BRONKHORST ®
Page 28 RS232 interface 9.17.027
5 PARAMETER INFORMATION
FLOW‐BUS is used for parameter value exchange between instruments and operation modules (keyboard or PC‐
interface). Parameter information consists of several properties for behaviour within the FLOW‐BUS system. In the
‘parameter properties’ table you will find a list of parameters and their properties. In the ‘parameter values’ table, the
values are described more detailed. This list consists mostly of parameters for mode settings.
Property description in parameter properties table:
Item Description
Parameter(DDE) unique parameter number (also used for DDE‐communication : P(x))
Name name of the parameter, used for parameter identification
process process where parameter is used on FLOW‐BUS module used for communication directly through
RS232 when filled in the table, this value has to be used (for parameters located in only 1 process)
when empty in the table, process has to be determined from the FLOW‐BUS system information
(for parameters located in more than one process, e.g. setpoint, measure);
FBnr(parameter) parameter number in process on FLOW‐BUS module used for communication directly through
RS232
VarType variable type for information about amount of bytes
 c (unsigned) char type 1 byte value 0..255
 I (unsigned) integer type 2 bytes value 0..65535
 f float type
4 bytes value +‐1.18E‐38..+‐3.39E+38 (IEEE‐floating point notation)
 l (unsigned) long type 4 bytes value 0..4294967295
data types > 1 byte are MSB first.
VarLength variable length to indicate length of string of chars used in combination with VarType c for
transportation of strings through FLOW‐BUS: value 0..65535
VarLength indicates the amount of bytes for a parameter type
 ‐2 indicates that a string is zero‐terminated, not defined for length
 X indicates a string with a length of X bytes (characters)
 0 means no info required, i.e. zero‐terminated.
Min minimum value of parameter allowed when parameter is read/written via RS232, the value will be
checked on this limit (error when out of limit)
Max maximum value of parameter allowed when parameter is read/written via RS232, the value will be
checked on this limit (error when out of limit)
Read indication if parameter is allowed to be read via FLOW‐BUS
Write indication if parameter is allowed to be written via FLOW‐BUS
Poll indication if parameter should be polled continuously by RS232 application in order to keep
(changing) parameter information up to date
Advanced indication if parameter is for advanced users only these are mainly parameters for
maintenance/service
Secured indication if parameter is secured for use through FLOW‐BUS reading this parameter is possible,
but changing it needs special handling
High security indication if parameter is highly secured (only few parameters) reading this parameter is possible,
but changing it needs special handling
Description short description about meaning of parameter or what it is used for
DDE str parameter DDE string (max. 10 characters), DDE value when parameter is not available on
instrument; also: until FlowDDE V4.58 used for parameter identification
Parameter acceptance:
Changing parameter values is possible when a parameter is not read‐only and not secured. The range
and type of parameters are described in the tables. When parameter values are out of range they will
be either 'clipped' on the nearest value allowed or you will get an error message: 'parameter value
error'.