Tektronix PWS4205, Programmer'S Manual

Page: 65 / 90

Status and Events
Registers
The registers in the event reporting system fall into two functional groups:
Status Registers contain information about the status of the power supply.
They include the Standard Event Status Register (SESR).
Enable Registers determine whether selected types of events are reported to
the Status Registers and the Event Queue. They include the Event Status
Enable Register (ESER), the Service Request Enable Register (SRER), the
Operation Enable Register (OENR), and the Questionable Enable Register
(QENR).
Status Registers There are six types of status registers:
Status Byte Register (SBR). (See page 3-3.)
Standard Event Status Register (SESR). (See page 3-4.)
Operation Condition Register (OCR). (See page 3-5.)
Operation Event Register (OEVR). (See page 3-5.)
Questionable Condition Register (QCR). (See page 3-5.)
Questionable Event Register (QEVR). (See page 3-6.)
NOTE.
The Questionable Event Register may be fi ltered by a positive transition
fi lter (QPTR) and a negative transition fi lter (QNTR). (See page 3-6.)
The Status Byte Register (SBR).
The SBR is made up of 8 bits. Bits 4, 5 and 6 are
de fi ned in accordance with IEEE Std 488.2-1992. These bits are used to monitor
the output queue, SESR, and service requests, respectively. (See Figure 3-2.)
Figure 3-2: The Status Byte Register (SBR)
Table 3-1: SBR bit functions
Bit Function
7 (MSB) OSB
Operation Status Bit.
Indicates that an operation
event has occurred.
6 RQS
Request Service.
Obtained from a serial poll. Shows
that the power supply requests service from the GPIB
controller.
PWS4205, PWS4305, PWS4323, PWS4602, and PWS4721 Power Supply Programmer Manual 3-3