Returns the current state of the specified direct-drive relay line (1 = ON, 0 = OFF).
•
I = driver number (1 to 8)
XDRS?
Direct Drive Line Group Query
Returns the current state of all specified direct-drive relay lines (1 = ON, 0 = OFF).
Status Reporting and Service Request Control
The SCG unit 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. Bit 2, the settled
condition bit, is 1 when the switch mechanism is 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, the
CNB?
query returns 4.
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 SCG unit. When
an event occurs, the status logic of the SCG unit sets the corresponding bit to 1. This register
can be read at any time because the bits stay set until the register is read at least once.
Status Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Self-Test
Error
Service
Request
Syntax
Error
Message
Available
0 Settled 0
Parameter
Error
•
Bit 7 (Self-Test Error) is set if a calibration error is detected after power-up or after the
self-test query (
TST?
) is executed. At all other times, the bit is 0.
•
Bit 6 (Service Request) is set when the interrupt request logic of the SCG unit detects a
reason to generate a service request interrupt on the GPIB interface.
•
Bit 5 (Syntax Error) is set when the parser detects a syntax error in a command mnemonic.
•
Bit 4 (Message Available) is set when a message is available in the output buffer.
Programming Guide –
30
