Need suggestion on instrument synchronization


George Hrysanthopoulos
 

Hello everyone,

This is my problem:

I have 2 instruments:
Tek 2753P SA
Siglent SSG 3021X Signal generator

Both have inputs for external Trigger. I would like to Sync
the 2 units so when the SG starts a sweep the SA follows.
Kind of like a tracking generator (which I have) but with
more options (the SG can generate all sorts of cool waveforms).

I need to have a trigger from .1s to maybe 30s +5V.

I can use my HP 3325B to generate a square wave
but I need that instrument to feed a circuit.

I was thinking of using a RPI to feed a buffer and generate the +5V
on multiple outputs. Also with software adjustable rate.

However, the members here may have a better solution.

Thanks in advance,

George Hrysanthopoulos, N2FGX


Harvey White
 

I'm not sure that it's any better, but I do have perhaps a lots cheaper idea.

Take the pulses from a pulse generator, or a square wave function generator, process them to the right amplitude and rise time, then feed both instruments from that.

If you want automation, then perhaps you have a 488 controlled function generator, but you'd want all the stuff that comes with that.  Cheaper than an RPI (unless you use an RPI-zero, in which case a chinese knockoff of an arduino would work as well, and you'd still need the controlling software in a computer unless you have a universal style control unit.

Unless you've looked, you might not know that RPI (Raspberry PI) boards are over 100 USD, and you'd want a touch display, so about another 60 or so.  The same functionality on an arduino could likely be less than 20 dollars, simply because the processors are far cheaper, as are the displays.

While I personally prefer ARM architecture (I do larger systems), there's a solid role for an Arduino.

Harvey

On 1/17/2022 7:47 PM, George Hrysanthopoulos wrote:
Hello everyone,

This is my problem:

I have 2 instruments:
Tek 2753P SA
Siglent SSG 3021X Signal generator

Both have inputs for external Trigger. I would like to Sync
the 2 units so when the SG starts a sweep the SA follows.
Kind of like a tracking generator (which I have) but with
more options (the SG can generate all sorts of cool waveforms).

I need to have a trigger from .1s to maybe 30s +5V.

I can use my HP 3325B to generate a square wave
but I need that instrument to feed a circuit.

I was thinking of using a RPI to feed a buffer and generate the +5V
on multiple outputs. Also with software adjustable rate.

However, the members here may have a better solution.

Thanks in advance,

George Hrysanthopoulos, N2FGX






George Hrysanthopoulos
 

Harvey,

You are right! 8GB RPI is close to $100.00
However, I do have a bunch RPIs for testing so no problem there.
Also, I would drive it from a web page. No need for touch display.

The way I see it, I would drive the 3.3V GPIO pin to an OPAMP first stage,
and the feed multiple OR/NOR/inverter TTL gates at +5V.

Put it all together on a nice board, etc...
However, now we are talking about a project here.

George

On 1/17/2022 20:05, Harvey White wrote:
I'm not sure that it's any better, but I do have perhaps a lots cheaper idea.

Take the pulses from a pulse generator, or a square wave function generator, process them to the right amplitude and rise time, then feed both instruments from that.

If you want automation, then perhaps you have a 488 controlled function generator, but you'd want all the stuff that comes with that.  Cheaper than an RPI (unless you use an RPI-zero, in which case a chinese knockoff of an arduino would work as well, and you'd still need the controlling software in a computer unless you have a universal style control unit.

Unless you've looked, you might not know that RPI (Raspberry PI) boards are over 100 USD, and you'd want a touch display, so about another 60 or so.  The same functionality on an arduino could likely be less than 20 dollars, simply because the processors are far cheaper, as are the displays.

While I personally prefer ARM architecture (I do larger systems), there's a solid role for an Arduino.

Harvey


On 1/17/2022 7:47 PM, George Hrysanthopoulos wrote:
Hello everyone,

This is my problem:

I have 2 instruments:
Tek 2753P SA
Siglent SSG 3021X Signal generator

Both have inputs for external Trigger. I would like to Sync
the 2 units so when the SG starts a sweep the SA follows.
Kind of like a tracking generator (which I have) but with
more options (the SG can generate all sorts of cool waveforms).

I need to have a trigger from .1s to maybe 30s +5V.

I can use my HP 3325B to generate a square wave
but I need that instrument to feed a circuit.

I was thinking of using a RPI to feed a buffer and generate the +5V
on multiple outputs. Also with software adjustable rate.

However, the members here may have a better solution.

Thanks in advance,

George Hrysanthopoulos, N2FGX









Harvey White
 

Interleaved:

On 1/17/2022 8:36 PM, George Hrysanthopoulos wrote:
Harvey,

You are right! 8GB RPI is close to $100.00
However, I do have a bunch RPIs for testing so no problem there.
Also, I would drive it from a web page. No need for touch display.
Lucky you to have so many.  I use ST Micro boards, which have significantly less resources.

I kinda like touch screen graphics displays, but I can do them.



The way I see it, I would drive the 3.3V GPIO pin to an OPAMP first stage,
and the feed multiple OR/NOR/inverter TTL gates at +5V.
Not needed to quite do that, look at a 74LVC145 (I think, tiny logic), it's a level translator SMT.  They are out there, and very cheap.  Bidirectional (needs a direction pin) and takes (say) 3.3 volts to 5.0, or 5.0 to 3.3.  I use them a lot.


Put it all together on a nice board, etc...
However, now we are talking about a project here.
If you do PC boards, it would be a simple one.  However, there's a 74245 (IIRC) that has dual VCC and is in dip format, and I think you can find 50 ohm driver chips fairly easily.

That can be easily made on perf board, and breadboarded to check the design.

Harvey



George

On 1/17/2022 20:05, Harvey White wrote:
I'm not sure that it's any better, but I do have perhaps a lots cheaper idea.

Take the pulses from a pulse generator, or a square wave function generator, process them to the right amplitude and rise time, then feed both instruments from that.

If you want automation, then perhaps you have a 488 controlled function generator, but you'd want all the stuff that comes with that.  Cheaper than an RPI (unless you use an RPI-zero, in which case a chinese knockoff of an arduino would work as well, and you'd still need the controlling software in a computer unless you have a universal style control unit.

Unless you've looked, you might not know that RPI (Raspberry PI) boards are over 100 USD, and you'd want a touch display, so about another 60 or so.  The same functionality on an arduino could likely be less than 20 dollars, simply because the processors are far cheaper, as are the displays.

While I personally prefer ARM architecture (I do larger systems), there's a solid role for an Arduino.

Harvey


On 1/17/2022 7:47 PM, George Hrysanthopoulos wrote:
Hello everyone,

This is my problem:

I have 2 instruments:
Tek 2753P SA
Siglent SSG 3021X Signal generator

Both have inputs for external Trigger. I would like to Sync
the 2 units so when the SG starts a sweep the SA follows.
Kind of like a tracking generator (which I have) but with
more options (the SG can generate all sorts of cool waveforms).

I need to have a trigger from .1s to maybe 30s +5V.

I can use my HP 3325B to generate a square wave
but I need that instrument to feed a circuit.

I was thinking of using a RPI to feed a buffer and generate the +5V
on multiple outputs. Also with software adjustable rate.

However, the members here may have a better solution.

Thanks in advance,

George Hrysanthopoulos, N2FGX













George Hrysanthopoulos
 

I keep forgetting about these level translators. There 2 different types on sparkfun.
Ok, I think I will breadboard one and see what happens.

George

On 1/17/2022 21:14, Harvey White wrote:
Interleaved:

On 1/17/2022 8:36 PM, George Hrysanthopoulos wrote:
Harvey,

You are right! 8GB RPI is close to $100.00
However, I do have a bunch RPIs for testing so no problem there.
Also, I would drive it from a web page. No need for touch display.
Lucky you to have so many.  I use ST Micro boards, which have significantly less resources.

I kinda like touch screen graphics displays, but I can do them.



The way I see it, I would drive the 3.3V GPIO pin to an OPAMP first stage,
and the feed multiple OR/NOR/inverter TTL gates at +5V.
Not needed to quite do that, look at a 74LVC145 (I think, tiny logic), it's a level translator SMT.  They are out there, and very cheap.  Bidirectional (needs a direction pin) and takes (say) 3.3 volts to 5.0, or 5.0 to 3.3.  I use them a lot.


Put it all together on a nice board, etc...
However, now we are talking about a project here.
If you do PC boards, it would be a simple one.  However, there's a 74245 (IIRC) that has dual VCC and is in dip format, and I think you can find 50 ohm driver chips fairly easily.

That can be easily made on perf board, and breadboarded to check the design.

Harvey



George

On 1/17/2022 20:05, Harvey White wrote:
I'm not sure that it's any better, but I do have perhaps a lots cheaper idea.

Take the pulses from a pulse generator, or a square wave function generator, process them to the right amplitude and rise time, then feed both instruments from that.

If you want automation, then perhaps you have a 488 controlled function generator, but you'd want all the stuff that comes with that.  Cheaper than an RPI (unless you use an RPI-zero, in which case a chinese knockoff of an arduino would work as well, and you'd still need the controlling software in a computer unless you have a universal style control unit.

Unless you've looked, you might not know that RPI (Raspberry PI) boards are over 100 USD, and you'd want a touch display, so about another 60 or so.  The same functionality on an arduino could likely be less than 20 dollars, simply because the processors are far cheaper, as are the displays.

While I personally prefer ARM architecture (I do larger systems), there's a solid role for an Arduino.

Harvey


On 1/17/2022 7:47 PM, George Hrysanthopoulos wrote:
Hello everyone,

This is my problem:

I have 2 instruments:
Tek 2753P SA
Siglent SSG 3021X Signal generator

Both have inputs for external Trigger. I would like to Sync
the 2 units so when the SG starts a sweep the SA follows.
Kind of like a tracking generator (which I have) but with
more options (the SG can generate all sorts of cool waveforms).

I need to have a trigger from .1s to maybe 30s +5V.

I can use my HP 3325B to generate a square wave
but I need that instrument to feed a circuit.

I was thinking of using a RPI to feed a buffer and generate the +5V
on multiple outputs. Also with software adjustable rate.

However, the members here may have a better solution.

Thanks in advance,

George Hrysanthopoulos, N2FGX
















George Hrysanthopoulos
 

I wonder how many outputs I can feed from one GPIO pin.
What is the fanout on those ?

e.x. if I use this board:
https://www.sparkfun.com/products/12009?_ga=2.260965709.1762212557.1642471173-1950750804.1640896801

Can I feed all 4 inputs from one GPIO pin ?
Sorry if this is best asked in a RPI forum.

George

On 1/18/2022 02:46, David Templeton wrote:
A PIC microcontroller would probably be more than able to do what you want, far simpler and more precise when it comes to timing.

It’s not very clear why you’d need the HP to create a square wave for the trigger, don’t both inputs just need an edge?




Harvey White
 

ARM processors (certainly the ST ones) drive 4 ma at the proper logic levels, and 20 ma at relaxed levels.

Using an LVC load should provide sufficient drive for more than one (0.16 ma = LSTTL, even less for LVC).

I'd still check the figures, but it would look good from here.

Harvey

On 1/18/2022 2:54 PM, David Templeton wrote:
You’d need to find the total load, and decide what your driving it with.

Can’t speak for raspberry pi, but many pics support 3.3v and 5v, and if using TTL levels then the thresholds are 0.8v and 2.0v

David

On 18 Jan 2022, at 19:20, George Hrysanthopoulos <george@maximaphysics.com> wrote:

I wonder how many outputs I can feed from one GPIO pin.
What is the fanout on those ?

e.x. if I use this board:
https://www.sparkfun.com/products/12009?_ga=2.260965709.1762212557.1642471173-1950750804.1640896801

Can I feed all 4 inputs from one GPIO pin ?
Sorry if this is best asked in a RPI forum.

George

On 1/18/2022 02:46, David Templeton wrote:
A PIC microcontroller would probably be more than able to do what you want, far simpler and more precise when it comes to timing.

It’s not very clear why you’d need the HP to create a square wave for the trigger, don’t both inputs just need an edge?