Hello,
I have a situation where it would benefit me to have an analog sensor off of the pcb (where it currently sits) and located remotely on a piece of equipment. Although I have several Ideas as to how best accomplish this, I cannot make a decision and would like some input before choosing a design path.
Setup:
Output is +/- 1.2 Vdc, and the max frequency of the signal is, from what I can figure, about 0.1 Hz, although I would like to allow for around 10Hz for future development of other parts of the system. The maximum current output is not published for this sensor as far as i can tell (freescale mma2260)
The sensors signal needs to travel approximately 10 ft through a noisy area into a shielded box which contains the control circuitry, the noise is from 3 large motors (> 1hp, 2 ac, 1 bldc all 200VAC) and several large relays switching ac loads (other motors, not in the immediate area)
The target of the signal is the control circuit which has a dspic30f micro.
Ideas:
1. I could convert the analog signal to something like CAN or serial RS232. I have enough experience in both to get the job done, however, this adds a level of complexity (local microcontroller, etc.) that I would rather not deal with.
2. Just keep it all analog back to the dspic. No comm, no extra micro, seems simple.
Questions:
Assuming #2 is chosen
1. should i put lp filters at the source or the destination or both or neither?
2. can i stick with all analog filters (not too familiar with dspic digital filters) or would it be better to do some digital (IIR, etc.) filtering?
3. are line drivers / recievers needed? would this be any different than the max232 ld/rec that i use for serial comms?
4. would increasing the output voltage from +/- 1.2 to say +/- 10V be a good idea? I can easily have 24v as well as the 3.3 or 5 needed for a sensor at the sensor location, in fact, i will probably make the low voltage on the sensor board from 24V with a small linear reg. If this is done, would a charg pump be adequate, i have had issues with imbalance when experimenting with them in the past and found the flyback topology to be easier for creating supplies on the negative end. is there a way to just use a negative linear?
Ok, I am rambling a little, lets start with this.
I have a situation where it would benefit me to have an analog sensor off of the pcb (where it currently sits) and located remotely on a piece of equipment. Although I have several Ideas as to how best accomplish this, I cannot make a decision and would like some input before choosing a design path.
Setup:
Output is +/- 1.2 Vdc, and the max frequency of the signal is, from what I can figure, about 0.1 Hz, although I would like to allow for around 10Hz for future development of other parts of the system. The maximum current output is not published for this sensor as far as i can tell (freescale mma2260)
The sensors signal needs to travel approximately 10 ft through a noisy area into a shielded box which contains the control circuitry, the noise is from 3 large motors (> 1hp, 2 ac, 1 bldc all 200VAC) and several large relays switching ac loads (other motors, not in the immediate area)
The target of the signal is the control circuit which has a dspic30f micro.
Ideas:
1. I could convert the analog signal to something like CAN or serial RS232. I have enough experience in both to get the job done, however, this adds a level of complexity (local microcontroller, etc.) that I would rather not deal with.
2. Just keep it all analog back to the dspic. No comm, no extra micro, seems simple.
Questions:
Assuming #2 is chosen
1. should i put lp filters at the source or the destination or both or neither?
2. can i stick with all analog filters (not too familiar with dspic digital filters) or would it be better to do some digital (IIR, etc.) filtering?
3. are line drivers / recievers needed? would this be any different than the max232 ld/rec that i use for serial comms?
4. would increasing the output voltage from +/- 1.2 to say +/- 10V be a good idea? I can easily have 24v as well as the 3.3 or 5 needed for a sensor at the sensor location, in fact, i will probably make the low voltage on the sensor board from 24V with a small linear reg. If this is done, would a charg pump be adequate, i have had issues with imbalance when experimenting with them in the past and found the flyback topology to be easier for creating supplies on the negative end. is there a way to just use a negative linear?
Ok, I am rambling a little, lets start with this.
