Actions
Forum Thread Details
  • State Not Answered
  • Replies 4 replies
  • Subscribers 305 subscribers
  • Views 1085 views
  • Users 0 members are here
Related
See a helpful answer?

Be sure to click 'more' and select 'suggest as answer'!

If you're the thread creator, be sure to click 'more' then 'Verify as Answer'!

GW Instek GPS 1850D Power Supply Clicking

char-123

I have a laboratory DC linear power supply model GPS-1850D. I have set this up in slave mode and connected my computer to control it. My computer has an output voltage range of 0 to 5 volts. I am currently trying to use a PID loop to take in a temperature reading (of peltier heater) through thermocouples, input that data into my computer, compare that temperature with my previous set point, and then output a voltage signal to control the power supply to get my Peltier heater to the desired temperature. 

I have the power supply in constant voltage mode, with the current limit around 4 volts. 

Whenever I try increase the PID setpoint by a few degrees Celsius, and the PID output voltage shoots up, the power supply will start clicking when it gets to around 4.3 volts. Why is it clicking and is it still okay to use?

Even when I increase the PID slightly, so that it the power supply would have to output 4.5 volts to keep the Peltier constant, the power supply starts clicking. It stops clicking when the voltage comes down, out of the 4.3 to 5 Volt range. 

Can anyone help me?

Also, I checked the current when the clicking is happening and it is at less than 1 amp, so I am not if the current limit is the problem or not. 

Parents
  • 0

    Sounds quite normal like Shabaz as mentioned. Linear power supplies will have multiple taps on the secondary of the transformer. This is to reduce the dropout voltage on the regulator stage. Say a 30Volt max DC powersupply to output 5 volts it has to drop a lot of voltage across the linear regulator ( as heat ) which is very ineficient. So Lab power supplies uses multiple outputs from transformer, rectify it and feed it to the regulator. This switching is controlled using relays. 

    You mentioned that you are using a PID controller. PID controller will adjust the output voltage based on the feedback loop. Thats probably why you are getting multiple clicks ( It's constantly adjusting the voltage up and down based on the feedback loop). What is the update rate for PID controller? If you drop the PID update rate you can observe less clicking, probably.

Reply
  • 0

    Sounds quite normal like Shabaz as mentioned. Linear power supplies will have multiple taps on the secondary of the transformer. This is to reduce the dropout voltage on the regulator stage. Say a 30Volt max DC powersupply to output 5 volts it has to drop a lot of voltage across the linear regulator ( as heat ) which is very ineficient. So Lab power supplies uses multiple outputs from transformer, rectify it and feed it to the regulator. This switching is controlled using relays. 

    You mentioned that you are using a PID controller. PID controller will adjust the output voltage based on the feedback loop. Thats probably why you are getting multiple clicks ( It's constantly adjusting the voltage up and down based on the feedback loop). What is the update rate for PID controller? If you drop the PID update rate you can observe less clicking, probably.

Children
No Data