HP SB manual Status Reporting and Service Request Control, Condition Register, Status Register

OPC?

Operation Complete

Returns the status of the input buffer.

•1 = the input buffer is empty, for example, all commands have been executed

•0 = the input buffer is not empty, for example, commands are still pending

IDN?

Identifier

Returns a string that identifies the manufacturer, the switch series, and the firmware level, for example, JDS Uniphase, SB Switch, 2.00

Status Reporting and Service Request Control

The SB switch maintains three eight-bit registers that are used for status reporting and for enabling the GPIB service request interrupt:

•Condition register

•Status register

•SRQ mask register

Condition Register

The condition register monitors the current state of the switch mechanism ( Table 9). Bit 2, the settled condition bit, is 1 when the switch mechanism has stopped at the desired channel and 0 when the switch is moving to a new output channel. The CNB? query command returns the value of the condition register. When the settled bit is true, CNB? query returns 4.

Table 9: Condition Register

Condition Register

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
0	0	0	0	0	settled	0	0

Status Register

The status register records errors and other events that have occurred in the switch (Table 10). When an event occurs, the switch status logic sets the corresponding bit to 1. The status register can be read at any time because the bits stay set until the register is read at least once.

Table 10: Status Register

Status Register

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
self-test	service	syntax	message	0	settled	0	parameter

Programming Guide – 29