5 channel low noise voltmeter

[Melbournian]

Hi, We are looking for a circuit to be made for a multi-channel voltmeter. The voltmeter must be low noise and cabable of measuring in the mV range so for example 0.01mV with good accuracy and stability and must be capable of measuring 5 channels simultaneously and then outputting these to a string which will be transmitted every 0.3 seconds via RS232/Twisted Pair/RS485 to be multiplexed by our system and then read using hyperterminal on a standard PC. one of the channels must be high impedance to allow for a long input cable length. Ideally the circuit board itself should be as small as possible with the dimensions around 15cm x 10cm.

We are looking for an electronics engineer who can design the circuit for something like this and then produce the prototype, we will be glad to pay for the services of anyone who can help us create what we want.

Please message me if you are interested in the work or know anyone who is.

 

[canadaelk]

Sounds like a data logger to me. Try dataq.com

 

[Melbournian]

Hi Canadaelk, Thanks for your reply but I need something which is customised to my requirements and can be designed by someone with sufficient electronics knowledge to take on the project and consult with me regarding specs during the design process and ongoing development.

 

[Melbournian]

Hi, also it is not a conventional data logger which needs to be downloaded but must transmit readings 3 times per second to a pc read by hyperterminal.

Thanks

 

[cowana]

0.01mV? Especially on long cable lengths? If you find someone who recons they can do that, make sure they seriously know what they are talking about - it is an almost impossible task.

 

[Melbournian]

The length of cable for measuring voltages of this magnitude is approximately 2m and the same for the rest but realistically that kind of accuracy is going to be hard to find but need to be able to measure 0.01 mV never the less in the same way that a Fluke could but over 5 channels at the same time and then digitise these voltages onto a string.