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Configure Hardware (HW) Alarm Output Settings

You can configures the hardware alarm output settings by clicking on the HW Alarm tab.

The instrument provides four hardware alarm outputs. You can use the alarm output lines to trigger external alarm lights, sirens, or send a TTL pulse to your control system. You can configure alarms to alert you when a reading exceeds specified limits on a channel during a scan. You can assign a high limit, a low limit, or both to any configured channel in the scan list. You can assign multiple channels to any of the four available alarms (numbered 1 through 4). For example, you can configure the instrument to generate an alarm on Alarm 1 when a limit is exceeded on any of channels 103, 205, or 320.

You can also assign alarms to channels on the 34907A Multi-Function Module or DAQM907A Multi-Function Module. For example, you can generate an alarm when a specific bit pattern or bit pattern change is detected on a digital input channel or when a specific count is reached on a totalizer channel. With the multifunction module, the channels do not have to be part of the scan list to generate an alarm.

To configure the alarm outputs:

  1. Select an alarm (or ALL alarms) in the Select Hardware Alarm column.
  2. Select either Tracking or Latch on Failure in the Mode area (the selected mode is used for all four outputs).
  3. Select the slope of the output pulse in the Polarity area (the selected Polarity is used for all four outputs). In the Fail = Low mode, a high-to-low TTL transition (falling-edge) is output to indicate an alarm. In the Fail = High mode, a low-to-high TTL signal (rising-edge) is output to indicate an alarm. A Factory Reset resets the Polarity to Fail = Low.
  4. To restore the default values, click the Restore Defaults button. To clear the alarm settings for the selected alarm(s), click the Clear from Instrument button. To clear the alarm queue for the logged alarm(s), click the Clear Alarm Queue button. When finished, click the Apply to Instrument button to store these settings in the instrument.

Note: Changing the slope of the output lines may cause the lines to change state.

See Also

Configure the Alarm Limits