Anti-Reset Windup (Suffix Letter F) Differential Relief Valve Calibration - Emerson Fisher 4195KA Instruction Manual

Instruction Manual
D200160X012
21. When the flapper is correctly aligned, set the proportional band to 400 percent in the desired controller action and
replace the proportional band indicator cover. If link 1 was disconnected, reconnect link 1 to the input element
using the same hole noted in step 8.
22. Remove supply pressure.
23. If the controller has the external feedback option, disconnect the outside tubing which connects the external
feedback connection to the output connection.
24. For controllers with anti‐reset windup (suffix letter F), remove the two machine screws, valve cover and two O‐rings
installed in step 1 of this procedure. Install the anti‐reset windup relief valve (key 55) with the arrow pointing in the
direction recorded in step 1.
Anti‐Reset Windup (suffix letter F) Differential Relief Valve Calibration
Calibration for the differential relief valve to relieve on rising controller output pressure
1. Provide a means of measuring the controller output pressure by connecting the controller output to a pressure
gauge (open‐loop conditions must exist). Do not apply supply pressure at this time.
2. Set the reset adjustment to 0.01 minutes per repeat (wide open) and the rate adjustment (4195KC controllers only)
to the OFF position.
3. For a controller with manual set point, move the set point indicator to the mid‐scale mark on the process scale. For
a controller with remote set point, adjust the remote set point pressure until the set point indicator is at the
mid‐scale mark on the process scale.
4. Set the proportional band to 100 percent in either the DIRECT or REVERSE action depending on the application
requirements.
5. Refer to figure 4‐3 for the location of the anti‐reset windup differential relief valve. For the differential relief valve to
relieve on rising controller output pressure, install the valve so the arrow on the valve points down. To change the
direction of the arrow, loosen the two mounting screws, pull the valve out, and reinstall the valve with the arrow
pointing down. Tighten the two mounting screws.
6. Provide a regulated supply pressure to the controller. Do not exceed the normal operating pressure in table 1‐6.
Note
Because of the high controller gain with the reset adjustment at 0.01 minutes per repeat, the controller output will not balance
perfectly in the following step. If the controller output is stable for approximately 5 seconds, it is adequately balanced.
7. Increase the process pressure (or vacuum for a vacuum controller) to the controller until the controller output
pressure balances at 0.4 bar (6 psig) for a 0.2 to 1.0 bar (3 to 15 psig) output range or 0.8 bar (12 psig) for a 0.4 to
2.0 bar (6 to 30 psig) output range.
8. Turn the reset adjustment to the CLOSED (4195KB controllers) or OFF (4195KC controllers) position.
9. Increase the controller output pressure in small steps [approximately 0.04 bar (0.5 psig)] by changing the process
pressure to the controller or by changing the controller set point. After each change in process pressure or set
point, the controller output pressure should quickly change and then stabilize at the new value.
10. Continue to change the controller output pressure in 0.04 bar (0.5 psi) steps and check the output pressure after
each step to make sure it stabilizes. At some point, the controller output will start to ramp upward to supply
pressure with no further change to the controller input or set point. Record the controller output pressure where
this ramping action begins because this is the point at which the differential relief valve has relieved.
11. To obtain the differential relief valve differential setting, calculate the difference between the original controller
output pressure in step 7 and the controller output pressure recorded in step 10.
12. If the differential pressure calculated in step 11 is incorrect for the application, adjust the differential pressure by
turning the differential relief valve adjustment screw shown in figure 4‐3. Turn the screw clockwise to decrease the
4195K Controllers
July 2018
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