Analog Input (Standard)
Operator Menu Location: Generic Hardware Operators Analog Inputs
Operator Bitmap:
Functional Description:
The Standard Analog Input generic hardware operator provides access to an analog input channel resource in the physical hardware. When the generic operator is linked to a specific hardware resource, its output value will correspond to the physical signal connected to that resource.
The operator can provide the raw signal value, in the unit of measure defined by the hardware configuration (e.g., 4-20mA, 0-10V, etc.). Alternatively, it can be configured to automatically map the raw signal into a user-defined representation as follows
Here, y is the operator output, x is the raw signal value, and represent the nominal range for the raw signal (e.g., mA, mA), is the user-defined value corresponding to , and is the user-defined value corresponding to . For example, suppose the hardware is configured to read a 4-20mA signal and is attached to a pressure transmitter with a dynamic range of 0-5800psi. Then, the operator would convert a reading of x=8mA to
User-Defined Properties:
Object Name. A string label that identifies the operator.
Scale. Either Hardware Defined or User Defined. In Hardware Defined mode, the operator output is the raw signal value in the unit of measure defined by the hardware configuration. In User Defined mode, the operator maps the raw signal into the user-defined scaling range.
Lo Range Scaled Equivalent. The operator representation of a signal at the low end of the hardware range when User Defined mode is selected.
Hi Range Scaled Equivalent. The operator representation of a signal at the high end of the hardware range when User Defined mode is selected.
Units. Engineering units label used for readability.
Comments:
•The value may be greater than the value.
•If the input signal is outside of the nominal hardware range, the operator representation may be outside of the user-defined range. For example, suppose the user-defined mappings are set to 0 and 100 and the hardware resource is configured for 4-20mA signals. A reading of 0mA, will be mapped to -25 (substitute x=0, , , mA, and mA into the equation above).
See Also:
Analog Output (Standard), Digital Input (Standard), Digital Input (Frequency Counter)