Reading Registers; Status Byte And Service Request (Srq) - Keithley 2750 User Manual

11-6 Status Structure

Reading registers

Any register in the status structure can be read by using the appropriate query (?) com-
mand. The following explains how to interpret the returned value (response message). The
actual query commands are covered later in this section
The response message for a register query will be a decimal value. This decimal value will
have to be converted to its binary equivalent. For example, decimal 19 in binary is 10011.
This binary value indicates that bits B0, B1, and B4 are set (1).

Status byte and service request (SRQ)

Service request is controlled by two 8-bit registers: the Status Byte Register and the Ser-
vice Request Enable Register.
Figure 11-3
Status byte and service request (SRQ)
Service
Request
Generation
RQS
*STB?
OSB
(B6)
Serial Poll
(B7)
MSS
&
OR
__
OSB
*SRE
(B7)
(B6)
*SRE?
OSB = Operation Summary Bit
MSS = Master Summary Status
RQS = Request for Service
ESB = Event Summary Bit
Mav = Message Available
Model 2750 Multimeter/Switch System User's Manual
Figure 11-3 shows the structure of these registers.
Status Summary Message
ESB MAV QSB EAV
(B5) (B4) (B3) (B2)
&
&
&
&
ESB MAV QSB EAV
(B5) (B4) (B3) (B2)
QSB = Questionable Summary Bit
EAV = Error Available
MSB = Measurement Summary Bit
& = Logical AND
OR = Logical OR
(Table 11-2 through
Read by Serial Poll
__
MSB Status Byte
(B1) (B0) Register
Read by *STB?
&
__
Service Request
MSB
Enable Register
(B1) (B0)
Table 11-5).