Output Queue; Standard Event Status; Status Byte Register - Chroma 63800 Series Operation & Programming Manual

Programmable AC/DC Electronic Load 63800 Series Operation & Programming Manual
9.4

Output Queue


The Output Queue stores output messages until they are read from the electronic load.

The Output Queue stores messages sequentially on a FIFO (First-In, First-Out) basis.

When there is data in the queue, it sets to 4 (MAV bit) in the Status Byte register.
9.5

Standard Event Status


All programming errors that have occurred will set one or more of the error bits in the
Standard Event Status register. Table 9-3 describes the standard events that apply to
the electronic load.

Reading of the Standard Event Status register will reset it to zero.

The Standard Event Enable register can be programmed to specify the standard event
bit that is logically ORed to become Bit 5 (ESB bit) in the Status Byte register.
Mnemonic Bit Value Bit
OPC 0
QYE 2
DDE 3
EXE
4
CME
5
9.6

Status Byte Register


The Status Byte register summarizes all of the status events from all status registers.
Table 9-4 describes the status events that are applied to the electronic load.

The Status Byte register can be read with a serial pull or *STB? query.

The RQS bit is the only bit that is automatically cleared after a serial poll.

When the Status Byte register is read with a *STB? query, Bit 6 of the Status Byte
register will contain the MSS bit. The MSS bit indicates that the load has at least one
reason for requesting service. *STB? does not affect the status byte.

The Status Byte register is cleared by *CLS command.
9-4
Table 9-3 Bit Description of Standard Event Status
Weight
Operation Complete. This event bit generated is responding
1 to the *OPC command. It indicates that the device has
completed all selected pending operations.
Query Error. The output queue was read when no data were
4
present or the data in the queue were lost.
8 Device Dependent Error. Memory was lost, or self-test failed.
Execution Error. A command parameter was outside the
legal range or inconsistent with the electronic load's
16
operation, or the command could not be executed due to
some operating condition.
Command Error. A syntax or semantic error has occurred, or
32 the electronic load has received a <GET> within a program
message.
Meaning