| ??? 07/25/06 13:37 Modified: 07/25/06 13:38 Read: times |
#121022 - Re: RTD & high voltage output. Responding to: ???'s previous message |
Dear Erik,
Thanks for your reply, RTD = Resistance Temperature Device. There are used for temperature measurement RTDs show resistance of 100 Ohms at 0 Deg Cel and 138.5 Ohms at 100 Deg Cel. They have postive temp coeff. Following is the dual RTD interface circuit I am using. "http://www.8052.com/users/prahlad/rtdinterface.GIF" The circuit uses a constant current source built around LM358 and the voltage developed across the RTD is then amplified by using 3 Amp classic Instrumentation amplifier. With this configuration the output is 1V to 3V. The problem arises when there is no RTD connected in the system as it opens up the feedback of the LM358 current sources causing the output to become Max Swing 13V. A current devider cant work as it will do more bad than good it does as it will cause my useful signal to reduce in magnitude. Thanks & Regards, Prahlad Purohit |
| Topic | Author | Date |
| Reistor in series in signal from Amp to ADC. | 01/01/70 00:00 | |
| You forgot the other Question | 01/01/70 00:00 | |
| Read the app notes | 01/01/70 00:00 | |
| What ADC? What application? | 01/01/70 00:00 | |
| Re: Application. | 01/01/70 00:00 | |
| That's not good | 01/01/70 00:00 | |
| a much more elaborate protection scheme must be im | 01/01/70 00:00 | |
| Re: RTD & high voltage output. | 01/01/70 00:00 | |
| what about a zener across the RTD? | 01/01/70 00:00 | |
| Some questions | 01/01/70 00:00 | |
| ADC details? | 01/01/70 00:00 | |
| datasheet does not contain because | 01/01/70 00:00 | |
| ADC details still missing! | 01/01/70 00:00 | |
| Yes ADC details Missing,. | 01/01/70 00:00 | |
| That's what we need the details for... | 01/01/70 00:00 | |
| what detail? | 01/01/70 00:00 | |
| Analog input circuitry and timing diagram | 01/01/70 00:00 | |
| Forum Power. | 01/01/70 00:00 | |
| Link? | 01/01/70 00:00 | |
| Re Link. | 01/01/70 00:00 | |
| if you use them, sign up | 01/01/70 00:00 | |
Thanks | 01/01/70 00:00 |