Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Boosting an Analog input signal

Boosting an Analog input signal

Boosting an Analog input signal

I work on really old CNC/Laser systems and noticed that when I use my analog input of 0 to -8v that when the laser it is feeding loads the signal down quite a bit. -8v becomes about -2v. These two pieces of equipment do not normally work together, but I have every other function working perfectly. So looking for a simple idea to boost its strength. Unfortunately the controller does not spec how much current it can deliver and the laser doesn’t spec how much current it demands. Ideally I’d also like to make it adjustable so the 0 to -8v will result in 0 to -5v, but that’s not critical.

"I am stuck on Band-Aid brand, 'cause they are stuck on me"

RE: Boosting an Analog input signal

How about a PID controller.Just use the Proportional feature.
High impedance input and robust output.

Ohm's law
Not just a good idea;
It's the LAW!

RE: Boosting an Analog input signal

A good start would be what is the brand and number of the controller and the laser?


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Boosting an Analog input signal

I don't know if this part is still available, or what the replacement might be, but we used to us the LH0063 buffer amp from National Semiconductor to probe interior nodes inside semiconductor chips. The LH0063 put out 100 mA at digital rates and had a gain bandwidth of nearly 100 MHz


TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Boosting an Analog input signal

Like thebard3 posted, there are lots of process signal buffers or isolators out there that would do all of what you want.

RE: Boosting an Analog input signal

Lots of good starting points for me, I never even thought of using a pid controller. I need to dig into the schematics I guess to see what amplifier the analog input is using and also the ic the laser is using.
The controller is a 1980’s vintage Anorad Anomatic II which is no longer supported by the manufacturer. The Laser is an old Raytheon SS550 welder/driller. Also old and there is only a small handful of us that support these anymore.
I did find the circuit originally used between these, it had an old AD510JH op amp that operated on + and -15vdc. Most of the electronics in the laser operated on +-15vdc. Would like something more modern, but I think I can still get those chips, so may just build the original circuit

I’m not an electronics engineer, I am more of a repair guy.

"I am stuck on Band-Aid brand, 'cause they are stuck on me"

RE: Boosting an Analog input signal

With a PID controller, with adjustable span and zero and outputs that are configurable with either an elevated zero or a non-elevated zero. You may further adjust the output voltages with voltage dividing resistors or generate a desired output voltage by dropping a milli-Amp output across a suitable resistor.
When calculating resistance values remember that the input resistance of the load should be part of the calculations.

Ohm's law
Not just a good idea;
It's the LAW!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close