Understanding Pinouts to make up TTL output cables.

[Robotstar5]

This thread brings back memories of some of the stuff I've had to solder, worst one was a high density 108 way plug, it would take me about 8 hours to do, luckily they only came in a couple of times a year.

 

[voipio]

I’d agree that looks like CAT5 cable and you are likely to struggle with the insulation melting. If you aren’t proficient at soldering or don’t have a fairly powerful soldering iron you may get frustrated. Usual easy option is to use a crimped RJ45 plug and a db9 to rj45 adapter e.g.

A 15W Antex soldering iron would easily be up to the job of soldering small gauge wire to DB9 connector pins. It's just a matter of technique. Keeping the soldering iron tip clean and tinned, when making the solder joints, is important.

 

[hotponyshoes]

For Soldering d-sub plugs and the like I mate them up into a matching socket before soldering as that helps hold the pins in place.

Iron tips are cheap enough that I just have one with a cup ground in (with a dremel) that fits around the pins.
Trick is to get the heat into the pin quickly and get the soldering done before it has time to melt the plastic.

There are some high quality dsubs available that have some other sort of material that's far more heat resistant.
It's green rather than white. Probably amphenol so probably cheaper just to pay someone else to do it!

Solder the top row first as you have to be careful not to melt one's you have already done

 

[sako243]

This is I think what I tend to use (albeit smaller diameters), will need to check the next time I'm in the office.

Do as @ajlelectronics suggests, flood the back of the pin with solder. Put the soldering iron on to heat up the pin a little, touch the solder to the pin once it's hot enough it should flow in nicely. Keep pushing the solder in and it'll help regulate the temperature like feeding the rod into a TIG weld. Once the pin is filled with solder then tin the cable, similar approach. Make sure all the strands are flooded thoroughly.

Add a small blob of solder to the tip of the soldering iron (the molten lead helps conduct the heat better rather than a perfectly smooth surface of the tip). Go back to the pin and heat it up again and once you see the solder melt gently push the wire into the pin. Remove the soldering iron and hold wire still until the solder has cooled.

You can gently clamp the connector into a vice to hold it still.

It's very much like gas welding, keeping an eye on colours / surface consistencies to know when the heat is right but a lot easier. Just take your time and don't rush.

I've done hundreds of DB9 connectors with both a 90W soldering iron, 30W and my little JBC Nase soldering iron. In fact the bigger the iron the easier it can be since the small one takes longer to get the heat in (with the smaller tips).

 

[dave h 2]

As everyone says D type plugs are easy to solder ----- when you use the right resin/rosin cored 60/40 solder.

Lead free from Screwfix etc has no core, melts at a higher temp and needs flux alleged to be non acidic that if left on copper pipe turns copper green and rusts steel even when wiped off.
Used on stranded wire this flux will run up the wire and corrode it as well as the bucket.
The extra heat required will make the insulation run away from the bucket much worse than even the proper solder does.

 

[Jelly_Sheffield]

Sorted, courtesy of a very nice bloke called Nick at Ripley Repairs.

Whilst I appreciate all the advice and will certainly try to get some practice in on future projects, in this instance I think exercising my "knowing when I'm beaten" skills was probably for the best.

 

[Jelly_Sheffield]

So I got things installed...

But there's a hitch...

The difference...

It would appear that the Sino DRO can't cope with the current requirements of the older scale system, and can't power itself on when they're connected.

Putting a multimeter across the 0V & 5V pins to measure the relative power demand:
- old Heidenhain scales measure 89Ω, equating to a power consumption of 0.28W
- a modern Sino scale measures 190Ω equating to a power consumption of 0.13W

It's not a lot, but as the counter is being built as cheaply as humanly possible, it's reasonable to think more than doubling the demand on its PSU will be causing an excessive voltage drop.

So now I either buy new scales, or do some surgery to add an external 5V supply to the system which will meet the demand.

Bit of a bugger really.

 

[dave h 2]

Most likely the extra demand of the 3 Heidenhain EXE 610's is to much
Will it work with just one input plugged in?

 

[Jelly_Sheffield]

Most likely the extra demand of the 3 Heidenhain EXE 610's is to much
Will it work with just one input plugged in?

No, even one is too much.

I will take a look inside at the weekend and try to work out if:

- it could be modified to have a different 5V power supply,
- it would tolerate me adding a separate higher power 5V source internally to the required pins,
- providing external power to the EXE610's is feasible (feels like a recipe for disaster somehow but I can't explain why), and
- I would need to spoof the original power source into thinking it's connected to a "normal" scale using a resistor to make any of those work.

I am well out of my comfort zone here.

 

[sako243]

The first option would be the best. Generally best not to add multiple power supplies in parallel, particularly when you don't know what the internal circuitry is.

 

[dave h 2]

Heidenhain bulbs are said to be run at half voltage so they last years (40) I assume that's done in the read head due the 5v listed on the pin outs, but .............
Devils advocate bit - I take it the display still works with the proper 3rd scale?

 

[Jelly_Sheffield]

The first option would be the best. Generally best not to add multiple power supplies in parallel, particularly when you don't know what the internal circuitry is.

Yeah, my assumption is that there's the potential to damage diodes and transistors that have been designed to deal with just enough current to do their job.

I suppose regardless of internal or external power, I need to put 5V across the two different types of scale and test if the current level in the TTL output is similar, then if there's a discrepancy check if the components in the counter could cope with it.

Unless I'm mistaken there's an actual standard for RS485 scales, but the various TTL protocols are proprietary whilst all effectively similar enough to be treated the same from a theoretical point of view.

Heidenhain bulbs are said to be run at half voltage so they last years (40) I assume that's done in the read head due the 5v listed on the pin outs, but .............
Devils advocate bit - I take it the display still works with the proper 3rd scale?

The counter and third sino scale works just fine together, plug the Heidenhain ones in and it dies temporarily.

It would be very satisfying to get this to work, and save a very awkward installation of new scales, but there's a pretty good chance I would find straight replacement easier than continuing with making things work at a time when I've had a massive run of things not quite going my way, and I just want a win.

 

[sako243]

Yeah, my assumption is that there's the potential to damage diodes and transistors that have been designed to deal with just enough current to do their job.

It's difficult to say without seeing the circuit board but something people forget is that electrical power can't be "pushed" into something. It's pulled by whatever needs it.

Having said that if it's not switched internally on the board (as in something between the rails supply pin and the 5V rail) there's nothing stopping you adding a wire in parallel to carry the current if you're worried about the PCB.

You'll just have to open it up and take some photos to show us and we can help narrow it down.

 

[Jelly_Sheffield]

It's difficult to say without seeing the circuit board but something people forget is that electrical power can't be "pushed" into something. It's pulled by whatever needs it.

My concern was that if some components of the Heidenhain system needs that additional current to function, everything else in circuit with them is subjected to the same current.

You'll just have to open it up and take some photos to show us and we can help narrow it down.

I will try to clear bench space so I can have a suitable working surface to disassemble the counter and take a look.

 

[sako243]

My concern was that if some components of the Heidenhain system needs that additional current to function, everything else in circuit with them is subjected to the same current.

That's what I meant - impossible to tell without opening it up. If you do open it up and find the 5V source you could buzz it through to the outputs to the scales. If it buzzes through with no resistance then you'll be safe to add a wire in parallel to take the current.