HP 8901B Operation And Calibration Manual

Operation Model 8901B
Clearing the Status Byte
NOTE
Remote-to-Local transitions will not clear the Status Byte.
Once bits in the Status Byte are set, they can be cleared by the following operations.
0 Reading the Status Byte by serial polling AFTER the condition is cleared. If the condition which
set the bits persists, those bits and the RQS bit will again be set.
0 Sending the Device Clear (DCL) message, presetting or powering up the instrument.
0 In Talk Status Only, the Status Byte is cleared each time the one-byte Data message is issued to
the bus.
0 Sending the Serial Poll Disable (SPD) bus command, or
0 Sending the Abort message.
Abort
Abort abruptly terminates all listener/talker activity on the interface bus and prepares all instruments
to receive a new command from the controller. Typically this
is an initialization command used to
place the bus in a known starting condition. The Modulation Analyzer stops listening or talking when
it receives the Abort message.
Pass Control/Take Control
The Modulation Analyzer does not respond to the Pass Control/Take Control message because it
cannot act as a controller.
Status Bit
The Modulation Analyzer does not implement parallel poll operations and therefore cannot send the
Status Bit message. The Status Bit should not be confused with the Status Byte which
was discussed
previously under “Status Byte”.
3-1 1. ADDITIONAL INFORMATION
Annunciators
REMOTE Light: Lights when the instrument is operating in remote mode. When the Modulation
Analyzer goes to local operation, the front-panel REMOTE annunciator turns
off.
LISTEN Light: Lights when the instrument is addressed to Listen.
TALK Light: Lights when the instrument is addressed to Talk.
3-32

HP 8901B Specifications

General

Brand	HP
Model	8901B
Category	Measuring Instruments
Language	English