5/12/2017
TECH-538/D.W.O. 23160
Page 58 of 189
Description of Functions
The five functions called during the
ACAL
routine are described as follows:
Position Sensor
The sensor calibration is a self-adjustment that sets the positioner’s Hall-Effect circuitry.
This function appears in the local display as
Sensor Calibration
and
Acal Sensor
.
Low/Zero
This function serves to set the fail position of the actuator/valve. Initially during this
calibration the valve is driven to the fail position (hard stop). The user will notice full pressure to Outlet
Port 2 and zero pressure to Outlet Port 1. This function appears in the local display as
Low/Zero
Calibration and
Acal Lo
.
High/Span
This function serves to set the fully energized (full travel) position of the actuator/valve.
Initially during this calibration the valve is driven to the fully energized (full travel) position (hard stop).
The user will notice full pressure to Outlet Port 1 and zero pressure to Outlet Port 2.
This function appears in the local display as
High/Span Calibration
and
Acal Hi
.
Transducer
The purpose of this function is to calibrate the positioner’s pressure transducer.
It should be performed only after a manual sensor calibration. This function appears in the local display
as
Transducer calibration
and
Acal Trnd
.
Auto PID
This procedure will override the positioner control and will modulate the valve in order
to automatically find out the best P (proportional), I (integral) and D (derivative) parameters.
This function appears in the local display as
Auto PID Turning
and
Acal PID
.
IMPORTANT:
After installing the positioner on the actuator for the first time, it is mandatory
to perform at least the first 4 calibration steps with success at least once.
