De bază pași pentru verificare normal închis supape cu a multimetru:
1. Set the ProcessMeter process multimeter to output mode, using the appropriate current range for the positioner.
2. Plug the output current test lead into the mA output jack.
3. Mutare funcția rotativă comutare de la the OFF poziție la primul mA ieșire poziție deasupra la select 4 la 20 mA interval.
4. Connect A proces multimetru la intrare terminale of the valve positioner.
5. to determine if the positioner fully closes the valve at 4 mA, adjust the output current to 4.0} mA using the the pushbutton. the valve should close.
6. în timp ce observând supapa pentru mișcare, apăs the grosier jos săgeată buton once to reduce the current to 3.9 mA. the valve should show no movement.
7. make sure there is no reverse pressure on the actuator when setting the position point at which the valve starts to open (this pressure keeps the valve closed when the controller input is 4.{0 mA). For spring-closed valves, there is no pressure on the diafragma. For double-acting piston type actuators, there should be no pressure on one side of the piston. To ensure there is no reverse presiune la the închide setare, the start point of valve opening can be set între 4.1 și 4.2 mA.
8. Check that the valve is open and press the arrow button on Coarse to adjust from 4.0 mA. Each time the Coarse up-arrow button is pressed, the current growth by 0.1 mA. The zero function of the valve positioner should be adjusted to set the valve to corespunz closed mode.
9. In order to check the fully open position of the the valve - known as the span position check - adjust the output current to 20 mA using the range button and wait for the the valve to stabilizse. While watching and feeling the valve move, press the Coarse up arrow button once to set to 20.1 mA. valve movement should be as small as possible and can adjusted us the span adjustment on the positioner.
10. folosind the Coarse control button, adjust the current level up or down between 20.1 mA and 19.9 mA. the valve stem should not move between 20.1 and 20 mA, and it should move slightly between 20 mA and 19.9 mA.
11. In most valve, the zero and span setpoints of the valve controller interact with each other; prin urmare, it is recomandable to repeat the test in the the complete closed and fully open positions, adjusting the valve position correct untill no further adjustment is required.
12. For valves with linear action, the linearity can be checked by setting the ProcessMeter process multimeter to 4 mA, steppping the current to 12 mA (50%) using the % step button and confirming that the valve position indicator is at the 50% travel position. If the valve is a non-linear type, refer to the valve manual for proper operation.
13. To check that the valve is functioning smoothly, turn the rotary switch to output mA and select Linear Slow Change. Make the process multimeter slash change the mA signal for a few cycles while watching any anormal valve movement. The valve should not oscillate or wobble, nor should there be any sluggish of movement at any step position of the linear slow change. Set the the valve controller gain to the point that gives the best response between these two conditions.
