Static calibration can create low and high pressure points for the 4 and 20 milliamp signals without rotating the actuator.
1) Determine high and low pressure that corresponds to the 4-20 mA signals.
2) Open the "Static Calibration" mode.
3) Use existing system pressure as a reference point or change using the increase.
4) Once desired reference setting is attained, consult spring chart to obtain pressure change per pilot revolution.
5) Calculate the number of turns between the reference pressure and the low and high values.
6) Enter these numbers into the "Turn to low and to high points". Numbers must be positive and can contain up to
decimal points.
7) Click "Download Calibration" button to complete actuator setup.
8) Click cancel button to restart calibration.
Example:
Required pressure range for 4-20 mA signals is 55 to 95 psi and system pressure is 70 psi. The 20-105 CRD-32 is
13 psi per turn. Therefore, 95 minus 55 divided by 13 = 1.92 turns is entered into the high point window. For the
low point settings: 70 minus 55 = 1.15 turns which is entered into the low point window.
(Remember to click "Download Calibration" button).
Spring Chart - PSI change per complete pilot revolution
CRD
15 -75 = 10.2 psi per turn
CRD
2-105 = 13
psi per turn
CRD 30-300 = 29
psi per turn
Static Calibration
Fig. 5
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