9
Control
ASCII Serial Communication
Alicat’s Serial Terminal is a pre-configured program for serial communication via the device’s
DB9 port. Download Serial Terminal for free at
.
The section below outlines several common commands. For more detailed information
on using the ASCII interface, please see the Serial Primer manual at
Establishing Communication
Connect the device to a computer through a COM port or virtual COM port, noting the
COM port number. Up to 26 devices can be connected to a single COM port.
The following are the default connection settings:
•
Baud: 19200
•
Data bits: 8
•
Parity: none
•
Stop bits: 1
•
Unit ID: A
Unit ID
Each device has a unique, single-letter ID using the standard 26-letter English alphabet
(e.g., A, B, C, etc.). The default ID is “A”. If more than one device on a COM port has the
same ID, data and commands become corrupted and do not report or execute properly.
When connecting multiple devices on the same COM port, connect one device at a time.
Provide a unit ID command for each device before connecting the next device.
To give the most recently connected device an unused ID:
Change the unit id command:
(
unit_id
@
desired_id
)
Taring the Device
Taring gives the device a zero reference for flow measurements, ensuring that the device
provides its most accurate measurements. It is recommended to tare the device:
•
After installation
•
When changing the device’s orientation
•
If the device is hit with any significant impact
•
After any significant changes to the temperature or pressure.
Tare the device:
(
unit_id
V
)
It is possible for the sensor zero to shift with changes in temperature and pressure. This
imost often indicated by the device not reading zero flow when at a 0 setpoint. The autotare
algorithm will automatically zero the device any time a 0 setpoint is given, after a small
delay (flow range dependent). For most flow ranges, the tare will execute in 2 seconds or
less after receiving a 0 setpoint. See the Serial Primer at
alicat.com/manuals
for more on
autotare.
Collecting Data
Live flow data can be collected in either Polling or Streaming mode.
Note:
Before collecting flow data, be sure to tare your controller. If autotare is enabled,
this can be accomplished by providing a setpoint of 0 and waiting for the flow readings
to reach zero.
Polling Mode
Polling the device returns a single line of data each time you request it. Your device was
shipped in polling mode with a unit ID of A, unless requested otherwise. To poll your device,
