Yokogawa Touch Screen GP20 - Manual (Page 8)

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IM 04L51B01-17EN
1.2 Operations over the Serial Interface
You can control the GX/GP by sending commands from a PC through the serial interface.
There are various types of commands: setting commands, output commands, operation
commands, communication control commands, and instrument information output
commands. Except for a few special commands, the commands are the same as those used
over an Ethernet network.
1.2.1 Preparing the Instrument
Connection
See section 1.2.3, “RS-232 Connection Procedure,” or section 1.2.4, “RS-422/485
Connection Procedure.”
GX/GP Configuration
Configure the GX/GP to use serial communication. For instructions on how to configure the
GX/GP, see section 1.17, “Configuring the Serial Communication Function (/C2 and /C3
options)“ in the Models GX10/GX20/GP10/GP20 Paperless Recorder User’s Manual (IM
04L51B01-01EN).
PC
The PC that you will use must meet the following requirements.
• The PC is connected to the GX/GP through the serial interface.
• The PC can run programs that you have created (see section 1.2.2, “Sending Commands
and Receiving Responses,” below).
1.2.2 Sending Commands and Receiving Responses
Programs
When you send a command to the GX/GP, it will return a response. You can control the
GX/GP by writing a program that sends commands and processes responses and then
executing the program. You need to create the programs.
Example: If you send the commands “FSnap,GET” from your PC to the GX/GP, the GX/GP
will return the snapshot data of its screen.
For details on commands and responses, see chapter 2, “Commands and Responses.”
Notes on Creating Programs
• For RS-232
When you connect a PC to the GX/GP through the serial interface, the GX/GP will be
ready to receive commands.
• For RS-422/485
The device that receives an open command (ESC O) from a PC will be ready to receive
commands. The connection will close in the following situations.
• When the GX/GP receives a connection-close command (ESC C).
• When another device is opened.
Example: If you open the device at address 1 and then open the device at address 2,
the connection with the device at address 1 will be closed automatically.