Automated loop testing for HART devices

Automated loop test properties for an analog input device

Define the following properties in the device definition’s Automated Loop Test Configuration pane. You can also apply an automated loop test template or a master device definition to populate some of the fields in the pane.

These properties apply to HART and WirelessHART devices with the HART analog input signal type. Changes to these properties do not require a download.

Test Readback Path
The path to the parameter in the associated module that the test uses for comparison. The test compares this parameter value to the Expected Readback Values at each test step.
Test Readback Scale
The low (EU0) and high (EU100) endpoints of the engineering units range for the expected value.
Number of Test Steps
The number of test points for the loop test.
Test Value (%)
For each step, the value sent to the device as its fixed output. The software calculates the Expected Readback Values based on the test value and the scale.
Expected Value Tolerance
The amount the actual value can deviate from the expected value and still pass the test, specified in percent of span. For example, if the low engineering units value is 0 and the low value tolerance is 1.5, an acceptable actual value would be 0 +/- 1.5.
Settling Time
The wait time between writing the test value and reading the expected value. Select from one of the values in the drop-down list. The software calculates the value of Automatic as follows: 3 seconds + (2 * module scan rate).
Apply Square Root
Select ON if the function block that references the device performs indirect square root linearization.