Hach-Lange SI792 C, SI792x C, SI792x C-FF, SI792x C-PA User Manual - Manual (Page 50)

Operation—Foundation Fieldbus
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6.2.2.3 Data processing
Use the L_TYPE parameter to apply a linearization function to the data.
• Direct—data is sent directly from the TB to the AI without
processing. The units for the XD_SCALE and OUT_SCALE
parameters must be identical.
• Indirect—data from the TB is linearly scaled from the input scale
(XD_SCALE) to the output scale (OUT_SCALE).
• Indirect square root—data is rescaled from the input scale
(XD_SCALE) and recalculated using a root function. Then the
value is linearly scaled to the output scale (OUT_SCALE).
6.2.2.4 Alarms
The AI block can generate block alarms and limit alarms. Use the
ACK_OPTION parameter to specify if an alarm must be acknowledged.
When the measured value status is “bad”, the AI block BLOCK_ERR
parameter indicates an Input Failure.
• Block alarms—a block error will be reported via the
BLOCK_ERR parameter (simulate active, input failure, block
configuration error, out of service (OOS)). The BLOCK_ALM
parameter sends the alarm status to the control system.
• Limit alarms—the measured value OUT falls outside of the limit
values (HI_HI_LIM, HI_LIM, LO_LIM, LO_LO_LIM).
If an alarm occurs, evaluate the following bus parameters:
• OUT parameter (currently measured value) in the Al block
• LAST_ERROR parameter in the transducer block
• SENSOFACE_STATUS parameter in the transducer block