remote on/off

[cps13]

Hi,

I need to build a circuit for a project at work and would like peoples opinions on what I have so far.

Outline:

I have an instrumentation amplifier which will be powered by a 9VDC battery. The amplifier outputs 4-20mA.
I am building a small circuit to attach to the battery and amp which will power the amp on/off when the user presses a button.
The signal to power off is an 18VDC signal for 10ms. This is sent via an acoustic beacon, it is a wireless signal.
The purpose of the circuit I am designing is to conserve battery life for the inst amp as it will not be easily accessible.
Ideally I would like a month standby life but at present am not close to this.

The circuit I have is

https://www.dropbox.com/s/dpdhlv4kasxzmoh/Untitled.jpg?dl=0

The LEDs are only present to identify which part of the circuit is active and will not be on the actual product.
Using the DMM on multi-sim I know that when one branch of the circuit is "on" there is 16.288mA flowing and in the "off" branch there is 65pA.

My main questions are:

In this circuit is there always going to be drawing 16mA in one branch?
Is there a better way to turn on/off, i.e. just using one toggle input rather than two?
What is the best way to simulate my 18V for 10mS in multisim?

Thanks all

 

[KMoffett]

So you have an instrumentation device, powered by a PP2 9V battery. It outputs a 9V(?)/4-20mA signal. The 4-20mA signals goes somewhere over a pair of wires? Or is this a stand alone data logger that you need to power on/off remotely.

Ken

 

[KrisBlueNZ]

Is this your "instrumentation amplifier"?


Where is the input?

Where is the output?

How is the control signal applied to it?

Does it work as an instrumentation amplifier in simulation?

 

[Chris13]

Is this your "instrumentation amplifier"?

View attachment 16730
Where is the input?

Where is the output?

How is the control signal applied to it?

Does it work as an instrumentation amplifier in simulation?

No that's not an instrumentation amp. That is a latch circuit.

My setup is:

A completely analogue instrumentation amp with a 0-10mV SIGNAL input. This is processed and given as a 4-20mA output.
The amp is POWERED by 2 x 9V PP3 batteries.

What I need to do is remotely turn this amplifier on and off.
I am completely open to the spec for turning it on/off except the signal to do so is 18V for 10mS.

The wireless aspect is all designed and working, so I have a wireless receiver which will output my 18V for 10mS already.

I think I may have gone into too much detail before. I will wire the power supply to my amp via my new circuit, so the amp can essentially be ignored as long as the output from my new circuit is at least 18V and 45mA. It is the new circuit which requires a method of being powered on/off remotely, I imagine putting a NO relay on the new circuit which will be closed by a flip-flop. I just would like peoples inputs about the best way they think to do it.

Many thanks,

 

[KMoffett]

Can you sketch out a block diagram of the "system". Is the 4-20mA part of the inst-amp or is it remote to it? Where is the "receiver" relative to the 18V batteries? How is the receiver powered?

Ken