Cla-Val 390-07/3690-07 - Manual (Page 24)

Calibration - Static and Dynamic
Before beginning the calibration process, determine if it is actual-
ly necessary! The actuator, if new, has been factory calibrated to
the spring range shown on the pilot and may not require further
calibration (30-300 spring range is calibrated from 40 to 140 psi).
Static calibration
Static calibration is a fast and convenient method of calibrating
the actuator by calculating the 4 and 20 mA values rather than
raise or lower the actual system pressure. Dynamic Calibration
requires that the system pressure is actually raised and lowered
to the system values desired.
The “Set Range” window will launch either Static or Dynamic cali-
bration. When the "Set Range" is activated, the following mes-
sage will be displayed. To continue with calibration, click "OK”, if
not click "Cancel".
1 Select "Static Calibration" Mode. The "CPC Motor"
check box should unchecked (Disabled).
2 Use increase and decrease buttons to put valve in control
of system. This will establish the reference set point.
3 Determine the pilot spring range. (Check nameplate label
on pilot). Get the pressure change per turn per pilot revolu
tion from the spring chart. Calculate the number of turns
between the reference set point and desired low and high
pressures.
4 These numbers are the "Value at 4 mA" and the Value at
20 mA". Numbers must be positive and can have up to 2
decimal places.
5 Enter the low value in set-point window (1).
6 Enter the high value in set-point window (2).
7 Click "Write Set Range" tab to complete actuator to
complete calibration.
Page 5
e-line list
OK
You are going to put the e-Drive / CPC in calibration Mode (Led Blinks Red/Green
X
Cancel
Example:
Valve is in control operating at 45 psi (3 bar).
The desired pressure at 4 mA is 30 psi (2 bar).
The desired pressure at 20 mA is 70 psi (4.8 bar).
From the spring chart, using a 15-75 spring, the pressure per turn is 10.2 psi (0.7 bar). The number of turns
to Low set point is equal to 45 psi (3 bar) minus 30 psi (2 bar) divided by 10.2 psi (0.7 bar) = 1.47 turns.
The number of turns to High set point is equal to 70 psi (4.82 bar) minus 45 psi (3 bar) divided by 10.2 psi
(0.6 bar) = 2.45 turns.