4194HA, HB, and HC Series 7. Increase the process differential pressure to the differential pressure unit until the controller output pressure is balanced at 6 psig (for a 3 to 15 psig output range) or 12 psig (for a 6 to 30 psig output range). 8. Turn the reset adjustment to the CLOSED (4194HB Series) or OFF (4194HC Series) position. 9. Increase the process differential pressure until controller output pressure changes in small steps (approximately 0.5 psig). After each change in input, the controller output pressure should quickly change and then stabilize at the new value. 10. Continue to affect the controller output pressure in 0.5 psi steps and check the output pressure after each step to make sure that it stabilizes. At some point, the controller output will start to ramp upward to supply pressure with no further change to the differential pressure input. Record the controller output pressure where this ramping action begins because this is the point at which the anti-reset windup valve has relieved. 11. To obtain the anti-reset windup 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, the differential can be adjusted by turning the anti-reset windup valve adjustment screw (see figure 3-1). Turning the screw clockwise will decrease the differential pressure. Turning the screw counterclockwise will increase the differential pressure. The anti-reset windup valve is set at the Fisher factory at approximately 5 psi differential pressure. 13. Repeat steps 7 through 12 until the required differential pressure is obtained. Calibration for the anti-reset windup valve to relieve on falling controller output pressure: 1. Plug the controller output connection or connect it to a pressure gauge if desired (open-loop conditions must exist). 2. Set the reset adjustment to 0.01 minute per repeat (wide open) and the rate adjustment (4194HC Series only) to the OFF position. 3. For a controller with manual set point, move the set point to 50 percent of the scale range. For a controller with remote set point, adjust the remote set point pressure until the set point indicator is at 50 percent of the scale range.
4. Adjust the proportional band to 100 percent DIRECT or REVERSE depending on the application requirements. 5. Refer to figure 3-1 for the location of the anti-reset windup valve. For the anti-reset windup valve to relieve on falling controller output pressure, install the valve so the arrow on the valve points up. If you must change the direction of the arrow, loosen the two mounting screws, pull the valve out, and reinstall with the arrow, direction reversed. Tighten the two mounting screws. 6. Turn on the supply pressure to the recommended value shown in table 1-4. Note Because of the high controller gain with the reset adjustment at 0.01 minute 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 differential pressure input to the differential pressure unit until the controller output pressure balances at 12 psig (for a 3 to 15 psig output range) or 24 psig (for a 6 to 30 psig output range). 8. Turn the reset adjustment to the CLOSED (4194HB Series) or OFF (4194HC Series) position. 9. Decrease the differential pressure until controller output pressure changes in small steps (approximately 0.5 psig). After each change in differential pressure input, the controller output pressure should quickly change then stabilize at the new value. 10. Continue to affect the controller output pressure in 0.5 psi steps and check the output pressure after each step to make sure that it stabilizes. At some point, the controller output will start to ramp downward to 0 psig 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 anti-reset windup valve has relieved. 11. To obtain the anti-reset windup 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, the differential can be adjusted by turning the anti-reset windup valve adjustment screw (see figure 3-1). Turning the screw clockwise will decrease the differential pressure. Turning the screw counterclockwise will increase the differential pressure. The anti-reset windup valve is factory set at approximately 5 psi differential pressure.
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