
11
Status
Description
0
Success
0x8001
Invalid command ID
0x8002
Invalid setting
0x8003
Requested feature is unsupported
0x8004
Invalid gas mix index
0x8005
Invalid gas mix constituent
0x8006
Invalid gas mix percentage
0x0001 to
0xFFFF
Process value. Command 14 will return current PID values in
hexadecimal format as command status values. These may overlap
status codes depending on the value.
COMPOSER™ Personalized Mixed Gas Compositions
Custom gas mixtures can be configured with 2-5 gases using the mix assembly. The
mix is a two-step process. First, the desired constituent gas indexes and percentages
must be written to the mix assembly followed by a write of the Mix Gas command (ID 2)
into command assembly. Assembly 104 accepts a 20 byte input, structured according
to the following table:
Gas Mix - Class 4, Instance 104, Attribute 3
Parameter
Type
Notes
Mixture Gas 1 Index
UINT
Mixture Gas 1 %
UINT
Mixture Gas 2 Index
UINT
Mixture Gas 2 %
UINT
Mixture Gas 3 Index
UINT
Mixture Gas 3 %
UINT
Mixture Gas 4 Index
UINT
Mixture Gas 4 %
UINT
Mixture Gas 5 Index
UINT
Mixture Gas 5 %
UINT
All 20 bytes must be passed to the assembly, and all gas indexes must be valid gas
index numbers. See product manual for a list of indices. A combination of mixtures
can be created by using an existing gas mixture index, 236-255. However, the accuracy
of the flow calculations may degrade with complex mixtures of gases with dissimilar
chemical properties.
Gas mix percentages are interpreted as integer hundredths of a percent and the total
percentage must sum to 100%. The mix will be performed with the first N gases that
have a non-zero percentage.
Once a valid gas mixture is defined in assembly 104, a new gas mixture index will be
created by passing command id 2 to instance 102, assembly 3. If one of the requested
mix gas indices does not exist, or the sum of gas percentages does not equal 100%, an
error will be returned in assembly 103 and the command will fail.