Technical data

• International Institute of Electrical and Electronics Engineers. IEEE Standard

488.2-1987, IEEE Standard Codes, Formats, Protocols and Common commands

For Use with ANSI/IEEE Std 488.1-1987. New York, NY, 1987.

IEEE 488.2 Mandatory and Optional Commands

In order to comply with the SCPI model as described in IEEE 488.2, the Serial

BERT implements certain mandatory commands. Other commands are

implemented optionally. For more detail on the IEEE 488.2 mandatory and optional

commands, see “IEEE Commands – Reference” on page 91 and “Optional

Commands” on page 96.

Overlapped and Sequential Commands

IEEE 488.2 defines the distinction between overlapped and sequential commands.

A sequential command is one which finishes executing before the next command

starts executing. An overlapped command is one which does not finish executing

before the next command starts executing.

The Serial BERT has the following overlapped commands:

• SENSe[1]:EYE:TCENter ONCE | ON | 1

• SENSe[1]:EYE:ACENter ONCE | ON | 1

• SENSe[1]:EYE:ALIGn:AUTO ONCE | ON | 1

• SENSe[1]:EYE:QUICk:TCENter ONCE | ON | 1

• SENSe[1]:EYE:QUICk:ACENter ONCE | ON | 1

• SENSe[1]:EYE:QUICk:ALIGN:AUTO ONCE | ON | 1

N O T E

It is not reliable to use wait statements in the control program to facilitate the use

of overlapped commands.

Because these commands may allow the execution of more than one command at

a time, special programming techniques must be used to ensure valid results. The

common commands *OPC, *WAI, and *OPC? can be used for this purpose. They

help synchronize a device controller with the execution of overlapped commands.

The behaviors of these commands, in brief, are as follows:

• *OPC

The *OPC command sets the Operation Complete (OPC) bit of the Standard

Event Status Register (ESR) when the No Operation Pending flag is TRUE ( No

Operation Pending flag is attached to each overlapped command). Until that

time, the controller may continue to parse and execute previous commands. It

4 SCPI Command Language

80 Agilent J-BERT N4903B High-Performance Serial BERT