Ceyear 4051 Series, User Manual

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6 Remote control
6.1 Basis of Remote Control
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6.1.4.1 Prevention of Overlapping Execution of Commands
In order to prevent overlapping execution of commands, multiple threads or commands can be applied,
including *OPC, *OPC? or *WAI. The three commands cannot be executed until the hardware is set. The
computer may be forced to wait for a certain period to synchronize certain events in the programming process.
The above methods are described below.
 Use multiple threads in the control program.
Multiple threads are used to complete waiting commands and synchronize the user interface and program,
that is, the command ―*OPC?‖ is executed in each single thread, with no blockage of GUI or program
threads.
 The use of three commands in synchronous execution is shown in the following table.
Table 6.5 Command Grammar
Method Execution Action Programming Method
*OPC After command execution, set the operation
completion bit in the ESR register. Set ESE BIT0;
Set SRE BIT5; send the overlapping
command and *OPC;
Wait for the service request signal (SRQ).
The service request signal means that the
overlapping command has been executed.
*OPC? Stop executing the current command and return to 1.
Only when the operation completion bit in the ESR
register is set, the command will be returned,
indicating that the previous command has been
processed.
End the current command processing before
executing other commands. Directly send the
command after processing of the current
command.
*WAI Before executing *WAI, wait for sending of all
commands. Then process the uncompleted
commands.
End the current command processing before
executing other commands. Directly send the
command after processing of the current
command.
6.1.5 Status Report System
The status report system is used to save all operation status information and error information of the current
instrument. The operation status information and error information are respectively saved in the status register
and error queue and can be inquired through the programmed interface.
 Structure of status register organization
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Application of status report system „„„„„„„„„„„„„„„„„„„„„„„„„„
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6.1.5.1 Structure of Status Register Organization
Register categories are as follows:
1) STB, SRE
The top register of the status report system is composed of the status byte (STB) and associated shielding
register, i.e. service request enabling register (SRE). STB is used to collect the information of registers of the
lower layers and save the general working conditions of the instrument.
2) ESR and SCPI status register
STB is used to receive the following register information:
 Relevant values of event status registers and event status enabling (ESE) shielding registers.
 SCPI status registers, such as STATus:OPERation and STATus:QUEStionable registers (defined by the
SCPI standard), including specific operations of the instrument. All the SCPI status registers have the