Distributor of Digi International: Excellent Integrated System Limited
Datasheet of 301-1141-01 - WATCHPORT TEMP SENSOR
Contact us: [email protected] Website: www.integrated-circuit.com
Watchport Installation Guide (90000406 Rev. H) – Page 9
Using the Watchport Sensor Interface
The Watchport line of USB attached sensor products present themselves to a user application by way of a
virtual serial port. This serial port is named as all standard serial ports in the form of COMx where x is a
number between 1 and 255. The number assignment can be configured using the Edgeport configuration
utility. (Refer to “The Edgeport Utility Program” on page 16.)
There are two basic types of sensing devices. The first type uses an ASCII command interface:
Watchport/H and Watchport/T. The second type uses an RS-232 modem signal interface: Watchport/P and
Watchport/W. The serial port can be opened with any serial parameters. Some sensors can be operated in
either mode: Watchport/A and Watchport/D.
The first type of sensing devices uses ASCII commands. All ASCII commands sent to the sensing device
must be terminated with a carriage return character
<CR>
. Multiple commands may be grouped together.
For example,
TCTF<CR>
would cause Celsius temperature followed by Fahrenheit temperature to be
returned in the response.
The format of the response sent from the Watchport sensor to the application is an ASCII printable
character string terminated by a
<CR>
. For example, sending the command
TF<CR>
generates a single
response string such as
+72.0000F<CR>
and sending a grouped command such as
TCTF<CR>
generates
two responses such
as +22.2200C<CR>
followed by
+72.0000F<CR>
.
Other response strings generated by the Watchport sensor include
Invalid Command<CR>
or
Sensor
Error<CR>
.
The second type of sensing device uses the modem signals: DSR (Data Set Ready), DCD (Data Carrier
Detect), or CTS (Clear To Send) to inform the application of the status of the sensor.
The following sections describe each sensor and its command or signal interface.
Additional information is available at www.digi.com and Digi International’s technical support.
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