MPE XR III series, Operator'S Manual

Page: 86 / 129

273.0E-2
<NRf> Extended format that includes <NR1>, <NR2> and <NR3>. 273
-273.0
2.73E2
<NRf+> Expanded decimal format that includes <NRf>, MIN, and
MAX 273
-273
2.73E2
MIN
MAX
4.4 IEEE-488 Event Processing
All of the SCPI subsystem commands in the previous section can be initiated using RS232,
optional IEEE-488, or optional Ethernet communications.
The IEEE-488 standard defines a method for status reporting. As illustrated in figure 4.1, the
method uses the IEEE-488.1 Status Byte (STB). Three bits of this byte are defined as: Master
Status Summary (MSS) Bit, Event Status Bit (ESB), and Message Available (MAV) Bit.
The Master Status Summary (MSS) is an unlatched bit. When the Status Byte Register is read
using a Status Byte Register query (discussed in Section 4.5.4), bit 6 will be 1 if there are any
conditions requiring service.
The STB is masked by the Service Request Enable Register (SRE) to allow the user to mask
specific or all events from setting the MSS bit to 1. The MSS bit is obtained by logical OR’ing
the bits of the enabled Status Byte Register.
The Event Status Bit (ESB) is set when one of the events defined in the Event Status Register
(ESR) (see Table 4.6) has occurred. As shown in figure 4.2 and like the STB, the ESR is masked
by the Event Status Enable Register (ESE) to allow the user to mask specific or all events from
setting the ESB to 1.
The Message AVailable (MAV) bit is set to 1 when a message is available in the output buffer.
4.5 IEEE-488 Standard Commands
The following sections describe the IEEE-488 Standard Commands.
4.5.1 Clear
This command clears all status register (ESR, STB and error queue).
Command Syntax: *CLS <>
74