API Command Reference Appendix A
A-16 NetScan User’s Manual
A - Assign Alarm Output
TYPE
System
EXECUTION
Deferred
SYNTAX
Achans,
output
Set alarm condition where chans is the channel(s) to assign to the digital
output.
chans may be in two forms: chan (for a single channel where
1 < chan < max) or first-last (for a range of channels where
1 < first < last < max), where max = 128 for NetScan.
output is the digital output number with which to associate the channel(s),
where 0 < output < 32.
A?
Query channels assigned to digital output.
DESCRIPTION
The Assign Alarm Output (A) command may be used to assign a particul ar c hannel, or range of channels, alarm
condition(s) to a particular digital output. This command allows internal alarm conditions to be sensed by
external devices via the 32 TTL-level digital outputs located on the back panel of the unit.
To use alarms, the channels in question must be part of the channel scan. Onc e the channels are configured (by
using the C command) and made part of the scan, the alarms are active. No t ri gger or t imebase assignment is
required. Alarming is totally independent of buffered operations.
If it is desired, an alarm event for a specific channel can be used as a st i m ulus for a digital output signal on the
back panel of the unit by using the A command to assign the channel to digital out put . This signal can be used
to set off an audible alarm or signal another device of the occurrence of the alarm c ondi t i on.
To unassign a digital alarm condition, use 0, which is the null output number. As s igning the null output number
to a channel(s) will disassociate the channel(s) from any digital output.
Thirty-two digital signals are available on the back panel of the master unit. Although analog input c hannels on
the slave units can be used to stimulate alarms, no digital output s ignals are available on the slave units.
Regardless of the number of slaves connected, 32 external alarm signals are available.
A channel programmed with alarm setpoints will not generate an alarm unless it is over a setpoint when the scan
occurs. For example, if a channel goes above then below an alarm threshold in-between scans, it will not be
detected or posted.
Alarm detection will generate an SRQ. You can then issue an alarm query (A?) which will return a 4-byte image
of the 32 alarm outputs.
EXAMPLE
PRINT#1,"C1-32, 1, -100.0,
100.0, 1.0X"
‘ Configure channels 1 - 32
PRINT#1,"A1,1X"
‘ Assign channel 1 alarm to digital output channel 1
PRINT#1,"A2-16,2X"
‘ Assign channels 2 - 16 alarms to digital output channel 2
PRINT#1,"A17-25,3X"
‘ Assign channels 17 - 25 alarms to digital output channel 3
PRINT#1,"A26-32,32X"
‘ Assign channels 26 - 32 alarms to digital output channel 32