Section 8
:
Status Model
Series 3700 System Switch/Multimeter Reference Manual
8-12
Document Number: 3700S-901-01 Rev. A / August 2007
Service request enable register
The generation of a service request is controlled by the Service Request Enable Register. This
register is programmed by the user and is used to enable or disable the setting of bit B6
(RQS/MSS) by the status summary message bits (B0, B2, B3, B4, B5, and B7) of the status
byte register. The summary bits are logically ANDed (&) with the corresponding enable bits of
the service request enable register. When a set (1) summary bit is ANDed with an enabled (1)
bit of the enable register, the logic ―1‖ output is applied to the input of the OR gate and,
therefore, sets the MSS/RQS bit in the status byte register. The individual bits of the service
request enable register can be set or cleared by using the *SRE common command or its script
equivalent. To read the service request enable register, use the *SRE? query or script
equivalent. The service request enable register clears when power is cycled or a parameter
value of 0 is sent with the *SRE command (i.e. *SRE 0).
SPE, SPD (serial polling)
For the GPIB interface only, the SPE and SPD general bus command sequence is used to serial
poll the Series 3700. Serial polling obtains the serial poll byte (status byte). Typically, serial
polling is used by the controller to determine which of several instruments has requested service
with the SRQ line.
Status byte and service request commands
The commands to program and read the status byte register and service request enable register
are listed below. Note that the table includes both common commands and their script command
equivalents. For details on programming and reading registers, see
Programming enable and
transition registers
(on page 8-8), and
Reading registers
(on page 8-9).
To reset the bits of the service request enable register to 0, use 0 as the parameter value for the
command (for example, *SRE 0).
Commands
Description
*STB?
or
print(status.condition)
Read status byte register.
*SRE <mask>
or
status.request_enable = <mask>
Program the service request enable register:
<mask> = 0 to 255
*SRE?
or
print(status.request_enable)
Read the service request enable register.
