32
D.
Configure the serial communication interface
Press the Menu button to enter the menu options to select the Utility option to enter the utility settings interface,
and then select I/O config to enter the port configuration interface. Select the RS232 option to configure RS232
communication.
Select the Baudrate option to set the baud rate.
Select Data bits to select the data bits.
Parity: select the check mode. There is no check bit by default.
Stop bits: set the stop bit, default 1 bit.
E.
Software Protocol
Since the hardware communication handshake is not used in the RS-232C interface, the multimeter uses the
character return method to reduce the possibility of data loss or data error in the communication. Please refer to
the following when compiling computer communication software:
1.
For command syntax and format, refer to Chapter 6 Command Reference.
2.
The controller transmits the command using ASCII code with <LF> as the termination character. ST1963
executes the command after the termination character is received.
3.
The character received by ST1963 will be echoed back to the controller again. The controller will not send
the next character until the last returned character is received correctly from ST1963. If the controller fails to
receive the character sent back from ST1963, the possible reasons are listed as follows:
The serial interface is not connected correctly.
Check if the instrument is set to use the RS232 interface and the baud rate is selected correctly.
While ST1963 is busy with executing a bus command, ST1963 will not accept any character from the
serial interface at the same time. So any character sent by controller will be ignored. In order to make
sure the whole command is sent and received correctly, any character without a returned character
should be sent again by the controller.
4.
ST1963 only sends information under following two conditions.
When a character is received normally, ST1963 will send the character back as a handshake.
When a query command is received, ST1963 will send the query response information.
5.
Once a query command is received, ST1963 will send the query response information immediately even if
the rest of commands have not been finished. So if the command includes two queries, the controller should
read the query responses twice. It is recommended that only one query is included in a single command.
6.
A query response is sent out in ASCII code with the preset termination character.
7.
Several query responses will be sent continuously with 1ms interval. The controller should be ready to
receive the responses, otherwise the response information will be lost.
8.
The controller should receive the query response termination character. Otherwise you have confused a
termination character with a returned character. At the same time the controller should receive the last
returned character before receiving a query response.
9.
For some commands that will take a long time to execute, for example reset command, the controller should
keep waiting to avoid the next command being lost when ST1963 is executing the former command.
10.
Communication software compiled with DOS application software should run under the pure DOS
environment supporting serial port. If it is running under WINDOWS, it may cause errors due to different
management methods of serial port.
