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SCPI Commands HMF series
Remote Control
12
Basics
SCPI Programmers Manual
1.6 Contents of the Status Registers
The SCPI standard contains an event handling system for all available interfaces that can be used
to be informed about the processes within the oscilloscope. According to the standard the oscil-
loscope replies only after receiving a query but the event handling enables the device to inform
the user that an extraordinary event took place.
Event Status Register (ESR) and Event Status Enable Register (ESE)
The ESR is defined in IEEE 488.2. The event status register can be read out using command
*ESR?. If a bit is set in the ESE and the associated bit in the ESR changes from 0 to 1, the ESB
bit in the STB is set. The ESE register can be set using the command *ESE and read using the
command *ESE?.
Status Byte (STB) and Service Request Enable Register (SRE)
The STatus Byte (STB) is already defined in IEEE 488.2. It provides a rough overview of the
instrument status by collecting the pieces of information of the lower registers. A special feature
is that bit 6 acts as the sum bit of the remaining bits of the status byte. The STB is read using the
command
The STatus Byte (STB) is linked to the Service Request Enable (SRE) register. Each bit of the STB
is assigned a bit in the SRE. Bit 6 of the SRE is ignored. If a bit is set in the SRE and the associa-
ted bit in the STB changes from 0 to 1, a service request (SRQ) is generated. The SRE can be set
using the command *SRE and read using the command *SRE?.
The SRER defines which interfaces may ask for permission to transmit. The GPIB interface is the
only one which has a hardware connection to the user for the transmission request (RQS bit);
the status of this line will tell whether an event happened.
All other interfaces (RS-232, USB, Ethernet) do not support this. If the user want to use the event
handling feature, he will have to read the status, e.g. by polling, from the instrument in every
case. Eventually, the status byte SBR will yield the desired information.
Error Queue
Each error state in the instrument leads to an entry in the error queue. The entries of the error
queue are detailed plain text error messages that can be looked up in the error log or queried via
remote control using SYSTem:ERRor[:NEXT]?. Each call of SYSTem:ERRor[:NEXT]? provides one
entry from the error queue. If no error messages are stored, the instrument responds with 0, „No
error“.
For further description of the error queue and the device error codes, please refer to chapter 2.