3-6
3
decimal but can be expressed in HEX, OCTAL or BINARY by prefixing the
number with a #H, #O or #B.
3.4.2
Event Status Register Set
The Event Status Register reports events that are common to all 488.2
devices. This includes events such as self test errors, command errors,
execution errors, power on and operation complete. The Power-on event
occurs at power turn-on and can be used to signal a power off-on occurrence.
The 488.2 Operation Complete event has no meaning for the 4807/2307/
4867/2367.
The Event Status Register is read with the
*ESR?
query and cleared with
the
*CLS
command. Use the
*ESE
commands to set the Event Status
Enable Register as shown in the following example:
*ESE 60
'enables error bits 2 through 5 for errors
*ESE?
'quires the enabling register setting
3.4.3
Questionable Registers and Digital Inputs
The Questionable Registers lets the user read the first fifteen digital input
lines and detect any changes in the digital inputs. Bit alignments are shown
in Figure 3-2. The Questionable Transition Register filters the inputs and
passes only the enabled state changes to the Questionable Event Register.
The Questionable Event Register bits becomes true (1) when the positive
transition bit is enabled and the associated condition register bit makes a 0
to 1 transition or when the negative transition bit is enabled and the
associated condition register bit makes a 1 to 0 transition. When both
transitions are selected for the same bit, the corresponding Questionable
Event Register bit sets whenever the digital input changes state. The
Questionable Event Register is cleared when it is read with the
STAT:QUES
query or by the
*CLS
command. The response is a decimal sum of the
binary values of the bits set to logical 1. e.g.
33 = bits 4 and 0 set to 1, all others set to 0
3.4.3.1 Monitoring Digital Inputs for State Changes
The unit can be set to monitor the digital inputs and generate a Service
Request when they change state. The following example sets the
