20
Serial Communication
Using Gas Select™ and COMPOSER™
To reconfigure your flow meter to flow a different gas, look up its gas number (
page 24
).
For more information on how Gas Select™ and COMPOSER™ work, see
page 13
. Here are
the commands:
Choose a gas:
[unit ID]
g
[Gas Number]
Example 1:
ag8
(reconfigures to flow nitrogen)
Example 2:
ag206
(reconfigures to flow P-10)
User mixes are selected in the same way. All COMPOSER™ gas mixes have a mix number
between 236 and 255.
Choose a user mix:
[unit ID]
g
[Gas Number]
Example:
ag255
(reconfigures for user mix 255)
Defining a new COMPOSER™ gas mix is faster using serial commands than using the front
panel. The basic formula for this is:
[unit ID]
gm
[Mix Name] [Mix Number] [Gas1 %] [Gas1 Number] [Gas2 %] [Gas2 Number]...
[Mix Name]
Use a maximum of 6 letters (upper and/or lower case), numbers and symbols
(period or hyphen only). This is equivalent to the short name when creating a mix via the
front panel (
page 14
).
[Mix Number]
Choose a number from 236 to 255. If a user mix with that number already
exists, it will be overwritten. Use the number 0 to assign the next available number to your
new gas. Gas numbers are assigned in descending order from 255.
[Gas1 %] [Gas1 Number]...
For each gas, enter its molar percentage up to 2 decimal places,
then its gas number (
page 24
). 2–5 gases are required, and the sum of all gas constituent
percentages must equal 100.00%. After creating a mix, the meter will confirm the new gas:
Example 1:
Create a mix of 71.35% helium, 19.25% nitrogen, and 9.4% carbon dioxide as
Gas 252, called “MyGas1”.
Command:
agm MyGas1 252 71.35 7 19.25 8 9.4 4
Response:
A 252 71.35% He 19.25% N2 9.40% CO2
Example 2:
Create a mix of 93% methane, 3% ethane, 1% propane, 2% nitrogen, and 1%
CO2, using the next available gas number, called “MyGas2”.
Command:
agm
MyGas2 0 93 2 3 5 1 12 2 8 1 4
Response:
A 253 93.00% CH4 3.00% C2H6 1.00% C3H8 2.00% N2 1.00% CO2
