| ??? 01/10/05 19:07 Read: times |
#84688 - Re Happy with PID Responding to: ???'s previous message |
Hi Steve
Do I get you right you heat and cool with one element? And your real problem is tolerance +/-0.05°C ? What sensor do you use ? How is it connected to the cell? Maby a second sensor on the other side of the Peltier cell might help? Did you check respons time? If your physical hardware is not symetric you need different PID parameters for up and down and for high and low of the setpoint. Maby you should apply power to the system "manualy" to the system for short time and see how it responds. Take care Peltier elements are absolutly not linear. I tested the cells of three manufactores and some were revers working for some time if power was swithed off. I did solve this putting a bypass resistor to the swithing transistor. But if you use heating and cooling one element this is difficult. Is the system you are heating / cooling always responding the same? I had to use four thermo sensors air inlet temperatur outlet temperatur and both sides of the Peltier cell to limit the overshot. Hope this helps. Peter |
| Topic | Author | Date |
| OT Step responses | 01/01/70 00:00 | |
| Step respons | 01/01/70 00:00 | |
| Happy with PID | 01/01/70 00:00 | |
| Re Happy with PID | 01/01/70 00:00 | |
| more details | 01/01/70 00:00 | |
| Making Use of Three Sensors | 01/01/70 00:00 | |
| Heat pipe? | 01/01/70 00:00 | |
| Minimizing Settling Time | 01/01/70 00:00 | |
| Timing | 01/01/70 00:00 | |
| Heat Transfer Rates and Efficiency | 01/01/70 00:00 | |
| Nice estimation | 01/01/70 00:00 | |
| Worked that out | 01/01/70 00:00 | |
| Segments of different PID parameters | 01/01/70 00:00 | |
| integrating cap | 01/01/70 00:00 | |
| Abruptly changing... | 01/01/70 00:00 | |
| Exaclty | 01/01/70 00:00 | |
| Have you Read Above? | 01/01/70 00:00 | |
| Sorry | 01/01/70 00:00 | |
| Maybe this can help? | 01/01/70 00:00 | |
| Interesting | 01/01/70 00:00 | |
| Reference | 01/01/70 00:00 | |
RE: Reference | 01/01/70 00:00 |