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Appendix A API Commands
ChartScan User’s Manual A-41
M
- Set SRQ Mask
TYPE
System
EXECUTION
Deferred
SYNTAX
Mmask
Use the IEEE 488 Service Request (SRQ) mechanism to inform the
IEEE 488 bus controller of certain conditions, where
mask
is in the form of
the number
nnn
such that
000
<
nnn
<
255
is summed from the
following conditions:
000
- Power-on default mask value
008
- SRQ On Scan Available
001
- SRQ On Alarm
016
- SRQ On Message Available
002
- SRQ On Trigger Event
032
- SRQ On Event Detected
004
- SRQ On Ready
128
- SRQ On Buffer Overrun
M?
Query the SRQ mask.
DESCRIPTION
The Set SRQ Mask (
M
) command uses the IEEE 488 Service Request (SRQ) mechanism to inform the IEEE 488
bus controller of the existence of several conditions in the Service Request Enable (SRE) Register. These
conditions are described in detail below. Multiple conditions can be enabled simultaneously. If multiple
conditions are contained within the same command string, each Set SRQ Mask command should be proceeded
by an Execute (
X
) command. The resulting SRQ Mask register value is the logical ORed value of the individual
values sent. Alternately, the entire value of all the desired conditions may be sent within one Set SRQ Mask (
M
)
command string. The programmed SRQ Mask remains enabled until the receipt of a
M000
command or the
detection of a Device Clear (DCL) or Selected Device Clear (SDC).
The following list outlines the possible conditions of the SRE:
M000
: This is the power-on default mask value. It disables the unit from generating service requests by clearing
the entire mask of the Service Request Enable (SRE) Register to zero.
M001
: SRQ On Alarm. Sending this command will enable the unit to generate an SRQ when it has recognized
that one or more channels has gone into alarm condition. Refer to the Configure Channels (
C
) command on how
to configure an alarm condition.
M002
: SRQ On Trigger Event. Sending this command allows the unit to generate a service request when it has
detected a valid trigger from the programmed trigger source.
M004
: SRQ On Ready. This command causes a service request to be generated when the unit has completed
executing a set of commands from the IEEE 488 bus controller. This is used to allow the bus controller to attend
to other bus matters while the unit is changing its internal state.
M008
: SRQ On Scan Available. Sending this command will cause the unit to generate an SRQ when at least
one scan is available to be read in the acquisition buffer.
M016
: SRQ On Message Available (MAV). Sending this command will cause the unit to generate an SRQ
when there is data available in the output queue to be read.
M032
: SRQ On Event Detected. Sending this command will cause the unit to generate an SRQ when at least
one of the defined events in the Event Status Register has occurred. Refer to the Set Event Mask (
N
) command
on how to define events.
M128
: SRQ On Buffer Overrun. Sending this command will cause the unit to generate an SRQ when it has
detected that an overrun of the acquisition buffer has occurred.
EXAMPLE
PRINT#1,“OUTPUT07;M0X”
‘ Clear the Service Request Enable (SRE) register
PRINT#1,“OUTPUT07;M1XM2X”
‘ Set the unit to SRQ on Alarm or Trigger
PRINT#1,“OUTPUT07;M?X”
‘ Read the current Service Request Enable (SRE)
register
PRINT#1,“ENTER07"
‘ Computer screen shows
M003
LINE INPUT #2, M$
PRINT M$