Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How to drop the voltage from a solid state output that leaks current?

Status
Not open for further replies.
G

Gravinus

Newbie level 3
Joined
Feb 6, 2018
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
41
How to drop voltage from a solid state output that leaks current?

Hello Everyone!

So I am trying to hook up a data logger to monitor the status of a solid state 24v output.

The problem is that my leakage current is giving me an input voltage to the logger of about .7-.9V and the logger requires a voltage under .4V to acknowledge a state change. I thought I could add a mechanical relay to open the circuit, but it won't acknowledge that either, it is looking for feedback across the input for an actual voltage below .4V.

Does anyone know an easy way to reduce the voltage present at the logger input to a sub .4V level? On the high side, I only need a signal at the logger above 2.8V, but it can be all the way up to 30V as well.

Any help is appreciated!
THANKS!!
 

Re: How to drop voltage from a solid state output that leaks current?

The first thing that comes to mind is to add a diode in series with a pull-down resistor between both devices, but you did not mention details on what kind of input is builtin this logger, nor on speed constraints.
 

Re: How to drop voltage from a solid state output that leaks current?

andre_teprom said:
The first thing that comes to mind is to add a diode in series with a pull-down resistor between both devices, but you did not mention details on what kind of input is builtin this logger, nor on speed constraints.
Click to expand...


Thanks for the reply! The specs on the logger are below, it is a Omega OM-CP-State101A. As for the speed I have it set for a 2 second sample rate currently.

Specifications
Input Connection: Removable screw terminal
Input Range: 0 to 30V
Input Low: <0.4V
Input High: >2.8V
Internal Weak Pull-Up: <60 µA
Input Impedance: >60 kΩ
Time Resolution: 4 Hz (reading rate selectable in software)
Reading Rate: 4 Hz to 1 every 24 hours
Memory: 406,323 readings; software configurable memory wrap
 

Re: How to drop voltage from a solid state output that leaks current?

Hi,

what about a resistive divider? 10k / 1k69 (GND)
You may increase the 1k69 as you like.

Klaus
 

Re: How to drop voltage from a solid state output that leaks current?

Thanks for the ideas guys.

Based on the logger specs listed above, would you be able to tell me the exact components I would need to implement either of the solutions above? I wouldn't have the first idea on how to properly spec them.

Much appreciated!
Ben
 

Re: How to drop voltage from a solid state output that leaks current?

Based on the following circuit, and referring to Klaus's suggestion:

Vin: Output from solid state relay
Vo: input from data logger
R1: 10K
R2: 1k69, 1k8, 2k2 (any of your choice)

Voltage_divider.png​
 

Re: How to drop voltage from a solid state output that leaks current?

THANKS, that is very helpful, appreciated!

One (hopefully last) question, what do I terminate the other side of R2 to?
 

Re: How to drop voltage from a solid state output that leaks current?

This is the GND (ground, not Earth) common to both devices. I'm afraid you're not fully aware of what you should do, so I would recommend the assistance of someone with a little more familiarity with electrical connections. In general, it is a good practice to first connect the ground, and then only the other cones to avoid burning an input by floating electric potential.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top