I/O Blocks > Discrete Input (DI) function block

Discrete Input function block alarm detection

Configure the DISC_LIM parameter to select the output (OUT_D) value that causes the alarm condition parameter (DISC_ACT) to be True and to set Discrete Alarm substatus in the output (OUT_D). You can enter any value between 0 and 255, although only 0 and 1 produce an alarm. However, you can enter state 255 to indicate that you never want an alarm indication.

Block errors

The following conditions are reported in the BLOCK_ERR parameter:

  • Simulate active — SIMULATE_D is enabled; therefore, OUT_D is not real.

  • Input failure/process variable has Bad status — The source of the block's process variable is bad.

  • Out of Service — The block is not being processed.

This block supports conditional alarming. Enabling conditional alarming makes additional parameters available for this block. On standard DI blocks, enable and disable conditional alarming from the Block Alarms dialog (right-click the block and select Assign Alarm). For DI blocks converted to fieldbus enable conditional alarming from the Block Alarms dialog or by using the CONDALM_ENABLED parameter.

Related information