Crystal APM Advanced Pressure Module - Manual (Page 8)

Communications  6
APM CPF Series Operation Manual
Communications
The APM interface uses a command – query – response protocol. Using this protocol the user can access the pressure measured by the module, as well as
control and monitor the status of all the essential functions of the module.
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INTERFACE DESCRIPTION
The APM can be remotely controlled using a PC terminal or computer program running the module in an automated system. A USB-based serial port con-
nection is required for remote operation. The serial port connection also powers the module. Once connected, a user can write programs with Windows-based
languages like Visual Basic.
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SETTING UP THE SERIAL PORT FOR REMOTE CONTROL
A USB to serial cable (available with part number APMCAL KIT ) is used for serial communications from the APM to a computer. To connect the module to a
computer, attach it to a USB-to-serial cable, connected and installed on a PC. Connecting the module to the cable will automatically power it on.
Note: Be sure to set the appropriate COM port in your communications software: 9600 Baud; No parity; 8 Data bits; 1 Stop bit; No hardware flow control;
Software flow control (XON/XOFF) recommended.
To verify the module has connected successfully, enter *IDN? within the communications program. This command will return information from the module.
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USING COMMANDS
Command Types
The APM may be controlled using commands and queries. All commands may be entered using upper or lower case. Refer to Remote Commands and Error
Codes for all available commands.
The commands are divided into the following types:
X Module Commands
Module Commands are used only by the module. For example, VAL? asks for the values displayed on the module display.
X Common Commands
Common Commands are standard commands used by most devices. These commands always begin with “ * ”. For example, *IDN? tells the module to return
its identification.
X Query Commands
Query Commands ask for Information, and always end with “ ? ”. For example, VAL? returns the current pressure reading of the module.