Instruction Manual Form 5207 April 2007
4195KA, KB, KC, and KS Controllers Startup for 4195KB and KC Series Controllers Perform the prestartup checks and, if necessary, calibrate the controller prior to this procedure. Note When performing the startup procedures, keep in mind that the initial settings are guidelines. They will vary depending on the actual process being controlled. 1. Be sure the supply pressure regulator is delivering the proper supply pressure to the controller. 2. For controllers with: Manual set point: Move the set point indicator to the desired set point. Remote set point: a. See figure 2-5 for the location of the remote set point connection. Connect an adjustable pressure source to the remote set point connection. b. Adjust the pressure source until the set point indicator reaches the desired set point. Remember: Increasing the remote set point pressure increases the set point. 3. Set the reset adjustment to 0.05 minutes per repeat for fast processes. Set it to 0.5 minutes per repeat for slow processes. For controllers with rate, set the rate adjustment to OFF. 4. Set the proportional band to 100 percent for fast processes. For slow processes, calculate the proportional band percentage from the equation below: P.B. + 200
Allowable Overshoot Pressure Span
For example: 200
0.14 bar ^ 13% 2.1 bar 5. If the controller is used in conjunction with a control valve, return the control valve to service by slowly opening the upstream and downstream manual control valves in the pipeline. Close the manual bypass valve, if one is used. 6. Tune the various controller actions.
4-4
Tuning proportional action: Create a load upset by momentarily changing the set point. Check for system cycling. If the system does not cycle, lower the proportional band setting (thus raising the gain) and disturb the system again by changing the set point. Continue this procedure until the system cycles. At this point, double the proportional band setting (proportional band setting ×2). Tuning reset action: Disturb the system. If the system does not cycle, speed up the reset by changing the setting to a lower value (faster reset). Disturb the system again. Continue this procedure until the system cycles. When the system cycles, multiply the reset time setting by a factor of three (reset setting ×3) and slow down the reset by changing the reset setting to the higher value. The reset is now tuned. Tuning rate action: For a controller with rate (4195KC Series), adjust the rate toward the higher setting until cycling occurs. When the system cycles, divide the rate value by a factor of three (rate setting á3) and decrease the rate by changing the setting to the lower value. The rate is now tuned. 7. Check the stability of the recommended proportional band setting by introducing a disturbance and monitoring the process. 8. Once stable control is attained, the process pointer and set point indicator should be in line. If they are aligned, return the set point to the desired value. If they are not, readjust the set point to the desired control point and proceed with step 9. 9. If the process pointer is within 5 percent of the set point indicator, turn the link 3 adjustment (see figure 6-13 or 6-21 for location) until the process pointer aligns with the set point indicator. Turn the link 3 adjustment screw clockwise to increase the process indication or counterclockwise to decrease it. If the process pointer is misaligned with the set point indicator by more than 5 percent of the scale span, perform the calibration procedures for 4195KB and KC Series controllers.
Calibration of 4195KB and KC Series Controllers WARNING To avoid personal injury or property damage resulting from the sudden release of pressure, do not exceed the operating limits given in this manual.