Agilent Technologies L4400 manual Viewing Stored Alarm Data, Enable pattern compare mode

Operating and Programming 3

Use CALC:COMP:MASK to designate the “don’t care” bits. Bits that you set to “0” in the mask are ignored. To enable the specified alarm mode, send the following command.

CALCulate:COMPare:STATe ON,(@<ch_list>)

Example: Configuring an Alarm on a Digital Input

The following program segment sets the digital pattern for the L4450A and then enables the pattern comparison mode. When the data read from the bank is equal to the comparison pattern, an alarm is generated on Alarm 2.

CALC:COMP:DATA:WORD #HF6,(@1201)		Set compare pattern (1111 0110)
CALC:COMP:TYPE	EQUAL,(@1201)	Generate alarm on match
OUTP:ALARM2:SOUR (@1201)		Enable alarms
CALC:COMP:STAT	ON,(@1201)	Enable pattern compare mode

To assign the alarm number to report any alarm conditions on the specified totalizer channels, use the following command.

OUTPut:ALARm[12]:SOURce (@<ch_list>)

To configure an alarm on a totalizer channel, specify the desired count as the upper limit using the following command.

CALCulate:LIMit:UPPer <count>,(@<ch_list>)

To enable the upper limit on the specified totalizer channel, use the following command.

CALCulate:LIMit:UPPer:STATe ON,(@<ch_list>)

Viewing Stored Alarm Data

If an alarm occurs on a channel as it is being scanned, then that channel’s alarm status is stored in reading memory as the readings are taken.

As alarm events are generated, they are also logged in an alarm queue, which is separate from reading memory. This is the only place where non- scanned alarms get logged (alarms generated by the digital modules).

The following command reads data from the alarm queue (one alarm event is read and cleared each time this command is executed).

SYSTem:ALARm?

The following command retrieves scanned readings and alarm data from reading memory (the readings are not erased).

FETCh?

L4400 User’s Guide 87