HP 8508A - Page 62

Operation
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SYSTEMS
Standard Event Status Register (SESR)
Figure 3-25 shows the operation of the Standard Event Status Register. This is a specific application of the event
registers discussed previously and its bit definitions are as follows:
Bit 5 - Command Error (CME) of
This bit indicates that the device has detected a command error. The following events cause a command error.
- 1, An IEEE 488.2 syntax error. This means that the device received a message which did not follow the syntax
defined by the IEEE488.2 standard. For example, it received data which violated the device listening format.
2. A semantic error occurred. For example, the device received an incorrectly spelled command. Another example
would be that the device received an optional IEEE488.2 command which it does not implement.
3. The device received a Group Execute Trigger (GET) inside a program message.
Bit 4 - Execution Error (EXE) |
This bit indicates that the device detected an error while trying to execute a command. It indicates that:
1. A <PROGRAM DATA> element received in a command was outside the legal range for the device, or incon-
sistent with the operation of the device.
2. The device could not execute a valid command due to some device condition.
Bit 3 - Device-dependent Error (DDE)
A device-dependent error is any device operation which did not execute properly due to some internal condition
_such as overrange. It indicates that the error was not a command, query, or an execution error.
Bit 2 - Query Error (QYE)
This bit indicates:
1. An attempt to read data from the Output Queue when no data was present.
2. That data in the Output Queue was lost. An example of this would be queue overflow.
Bit 0 - Operation Complete (OPC)
This bit indicates that the device has completed any pending operations and is ready to accept new commands. This
bit is generated only in response to the Operation Complete (*OPC) command.
SESR Operation
The SESR operates in the same manner as the Event Registers described earlier. It can only ve cleared by:
‘1. a Clear Status command (*CLS).
2. reading it (*ESR?).
3. a power-on transition .
The associated Standard Event Status Enable Register is written with the Enable Status (*ESE) command and read
with the Enable Status (*ESE?) query.
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