Hi all,
I'm using NI USB-6001 to control the temperature of two rope heaters in the system. But I have a hard time controlling the temperature in two situations:
1. The setpoint for one heater is 280 C. But, it reaches only 270 C and maintains 270 C (applying PID control). I tried to use only P control to check if it reaches a higher temperature when I set a higher setpoint, but it always reached 270 C and was maintained even when the setpoint was 280, 290, and 300 C.
2. The other heater shows huge fluctuation at the high-temperature setpoint (> 270 C). When the setpoint temperature is less than 270 C, the temperature control works well. However, if I set the setpoint to 270 C or higher, it starts to fluctuate with the range of ±20 C. I tried to use P control to see if it reaches a steady-state at the setpoint more than 270 C, but it couldn't reach a steady-state and just started to fluctuate around the set point.
I'm wondering if this is a programming issue or others. I inherited this system from my senior and am quite new to Labview and DAQ systems so any direction would be greatly appreciated.