ASCII Communication
January 2023
•
Rev. 0
• Standard Devices User Manual
31
Additional columns, including status codes (
), may be present to the right of the gas label column. The unit ID appears
in the data frame only when the device is in polling mode.
Setpoint
Controllers
Before attempting to send a setpoint to your controller serially, confirm that its setpoint source is set to
Serial/Front Panel
(
When sending a new setpoint, the data frame returns the new setpoint value when it has been accepted as a valid setpoint.
The
controller reads the requested setpoint using the current engineering units that have been selected (
New setpoint:
unit_id
S
floating_point_number_setpoint
Example:
AS 15.44
(setpoint of +15.44 SLPM)
When using a bidirectional controller, negative setpoints are sent by adding a hyphen for the minus sign (
−
):
Example:
AS -15.44
(setpoint of −15.44 SLPM)
Gas Select™ and COMPOSER™
Mass Flow Devices
To reconfigure your flow devices to flow a different gas, look up its gas number (
). For more information on how Gas
Select™ and COMPOSER™ work, see
Choose a gas:
unit_id
G
gas_number
Example 1:
AG 8
(reconfigures to flow nitrogen)
Example 2:
AG 206
(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 (
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 percentage of the mixture up to 2 decimal places, then its gas number (
).
2–5 gases are required, and the sum of all gas constituent percentages must equal 100.00%. After creating a mix, the controller
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% carbon dioxide, 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
