Product Manual

LCD and Remote Interface Setup Procedures
Command Use 5
5-15
5. Event Status Register (ESR)
The Event Status Register is a two-byte register in which the higher eight bits are
always 0, and the lower eight bits show different conditions of the Product. The ESR
is cleared (set to 0) when the power is turned on, and each time it is read.
Parameters are necessary for many of the remote commands. Incorrect parameter use
causes command errors to occur. When a command error occurs, bit CME (5) in the
Event Status Register (ESR) goes to 1 (if enabled in ESE register), and the error is
logged in the error queue.
6. Event Status Enable (ESE) Register
A mask register named the Event Status Enable register (ESE) lets the controller
enable or mask (disable) each bit in the ESR. When a bit in the ESE is 1, the related
bit in the ESR is enabled. When an enabled bit in the ESR is 1, the ESB bit in the
Serial Poll Status Byte also goes to 1. The ESR bit stays 1 until the controller reads
the ESR, does a device clear, a selected device clear, or sends the reset or *CLS
command to the Product. The ESE is cleared (set to 0) when the power is turned on.
7. Bit Assignments for the ESR and ESE
The bits in the Event Status Register (ESR) and Event Status Enable register (ESE)
are as shown in Table 5-8.
Table 5-8. Event Status Register (ESR) and Event Status Enable (ESE) Registers
15 14 13 12 11 10 9 8
0 0 0 0 0 0 0 0
7 6 5 4 3 2 1 0
PON 0 CME EXE DDE QYE 0 OPC
PON Power on. This bit is set to 1 if line power has been turned off and on since the last time the
ESR was read.
CME Command error. The IEEE-488 interface of the Product encountered an incorrectly formed
command and placed an error code in the error queue. The command FAULT? can be used
to fetch error codes from the error queue, which is described in more detail below.
EXE Execution error. An error occurred when the Product tried to execute the last command an
error code was placed into the error queue. This could be caused, for example, by a
parameter being out of range. The command FAULT? can be used to fetch error codes from
the error queue, which is described in more detail below.
DDE Device-dependent error. An error related to a device-dependent command has occurred.
QYE Query error. The Product was addressed to talk when no response data was available or
appropriate, or when the controller failed to retrieve data from the output queue.
OPC Operation complete. All commands previous to reception of a *OPC command have been
executed, and the interface is ready to accept another message.
8. Programming the ESR and ESE
To read the contents of the ESR, send the remote command, *ESR?. The ESR is
cleared (set to 0) each time it is read. To read the contents of the ESE, send the
remote command, *ESE?. The ESE is not cleared when it is read. When you read
registers, the Product shows a decimal number that when changed to binary refers to
bits 0 through 15.
9. Output Queue
The output queue is loaded when a query is processed, and holds a maximum of 250