Alicat MC Series Mass Flow Controller - Manual (Page 31)

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Unless otherwise specified each unit is shipped with a default address of capital A.
Other valid addresses are B thru Z.
Once you have established communication with the unit and have a stream of
information filling your screen:
1. Type *@=A followed by “Enter” (or using the RS-232 / RS-485 communication
select menu, select A as identifier and exit the screen) to stop the streaming
mode of information. Note that the flow of information will not stop while
you are typing and you will not be able to read what you have typed. Also,
the unit does not accept a backspace or delete in the line so it must be typed
correctly. If in doubt, simply hit enter and start again. If the unit does not
get exactly what it is expecting, it will ignore it. If the line has been typed
correctly, the data will stop.
2. You may now poll the unit by typing A followed by “Enter”. This does an
instantaneous poll of unit A and returns the values once. You may type A
“Enter” as many times as you like. Alternately you could resume streaming
mode by typing *@=@ followed by “Enter”. Repeat step 1 to remove the
unit from the streaming mode.
3. To assign the unit a new address, type *@=New Address, e.g. *@=B. Care
should be taken not to assign an address to a unit if more than one unit is on
the RS-232 / RS-485 line as all of the addresses will be reassigned. Instead,
each should be individually attached to the RS-232 / RS-485 line, given an
address, and taken off. After each unit has been given a unique address, they
can all be put back on the same line and polled individually.
Sending a Set-point via RS-232 / RS-485: To send a set-point via RS-232 / RS-485,
“Serial” must be selected under the “Input” list in the control set up mode.
Method 1: Set-point may be set in floating point in serial communication using
serial command (UnitID)SX.YZ
Example: AS4.54 results in Unit ID A changing set-point to 4.54.
Method 2: Type in a number between 0 and 65535 (2% over range), where 64000
denotes full-scale flow rate, and hit “Enter”.
The set-point column and flow rates should change accordingly. If they do not,
try hitting “Enter” a couple of times and repeating your command. The formula
for performing a linear interpolation is as follows:
Value = (Desired Set-point X 64000) / Full Scale Flow Range
For example, if your device is a 100 slpm full-scale unit and you wish to apply a
set-point of 35 slpm you would enter the following value:
22400 = (35 slpm X 64000) / 100 slpm
If the controller is in polling mode as described in Changing from Streaming
Mode to Polling Mode, the set-point must be preceded by the address of the
controller. For example, if your controller has been given an address of D, the
set-point above would be sent by typing:
D22400 followed by “Enter”