I NEED ADVICE ON WIRING DRO ENCODER HEAD

[riftol]

I was moving a rotary table off of the end of my mill's table and it slipped from my hands.

The very heavy rotary table fell into the U-shaped slack of the cable that connects the encoder head to the DRO's display.


Where they were soldered together, the encoder head's 4 wires pulled away from the cable's 4 wires that go to the DRO display.

My problem is that all the colors of the 4 wires on the encoder head do not match all the colors of the 4 cable wires.

The DRO is a Sargon Model 650.


The encoder head has 4 wires:


A black wire

A green wire

An orange wire

A white wire that has some red striping on it





The cable has 4 wires:


A black wire

A red wire

A blue wire

A green wire



Should I solder black to black and green to green and then try orange to blue and the white wire with red striping to red?


I don't mind trying different combinations until I find the right one but I want to be sure that I can't damage any of the electrical/computer/display components if I solder the wrong wires together.


Is it OK to try soldering different combinations?

Any advice will be much appreciated.

[bigcalidave]

NO!

[bigcalidave]

Just had to get that out there first. No you don't try different combinations. You need to disassemble both ends of the cable, figure out which wire is which, contact the manufacturer for a schematic or assistance, and do it right.

[riftol]

Just had to get that out there first. No you don't try different combinations. You need to disassemble both ends of the cable, figure out which wire is which, contact the manufacturer for a schematic or assistance, and do it right.

The DRO is no longer manufactured.

I tired to find schematics and found zilch.

[bauern]

Open up one of the other heads and see how they are wired.

[riftol]

Open up one of the other heads and see how they are wired.

The mill I got was set up only with 1 encoder head /encoder block / cable /scale for the X-axis.

[bauern]

From your description, it sounds like the break is in the cable and not at the end "terminals". If they were soldered together, its possible someone pieced it together. Who makes the scale? Can you "read" the break in the solder to see which wires pair up?

EDIT: Is the DRO end a 25 pin connector? Found this: http://www.diyprojects.info/bb/ftopic74793.html

14 = gnd
15 = +5V
1 = quadrature input 1 (TTL levels)
2 = quadrature input 2 (TTL levels)

Still need to know the scale end wires.

[riftol]

From your description, it sounds like the break is in the cable and not at the end "terminals". If they were soldered together, its possible someone pieced it together. Who makes the scale? Can you "read" the break in the solder to see which wires pair up?

EDIT: Is the DRO end a 25 pin connector? Found this: http://www.diyprojects.info/bb/ftopic74793.html

14 = gnd
15 = +5V
1 = quadrature input 1 (TTL levels)
2 = quadrature input 2 (TTL levels)



Still need to know the scale end wires.

bauern: Thank you for your assistance.


The cable's plug that plugs into the DRO's display unit has four pins that plug into tiny sockets on a circuit board (I think that's what it is called) inside the DRO's display.

I used a continuity tester to determine which of the plug's pins match up with the four wires at the other end of the cable where those wires were soldered to the encoder head's wires.

The scale is a strip of glass.

No wires were connected to the scale by which I mean the scale itself is not a wired component.

The wired encoder head slides along the bottom of the scale as the scale, which is mounted to the table, moves leftward or rightward.

AFAIK, and I'm pretty sure I'm right, the entire DRO including scale was made by Sargon.


It is possible that the cable was also damaged where the rotary table fell on it.

If that is the case the cable is of sufficient length to cut the cable at that point of damage and solder its wires to the encoder head's wires.

I took the encoder block off the mill and removed the encoder head from it so I am positive that the encoder head's 4 wires pulled away from the cable's 4 wires where they had been soldered together.

[Gunsmith Dan]

Without a wiring schematic to tell what voltages and signals are sent on which wires yes you will damage stuff on a dc circuit sending the wrong voltage or sending voltage the wrong way.


If you know how to use a Multimeter / VOM then you can check the voltages and maybe get lucky.

Normally for DC (not saying in this case):

Red= + voltage

Black= - voltage

Green= ground

In this case you have 4 wires and so looks like power is not constant and separate from the signals but the power is pulsed (which makes sense for a rotary table).

So you can use the multimeter and run the system and see what signals are sent and which voltages you get and get lucky but without a wiring schematic you have a 50/50 chance of damaging something. If the wires where crushed then yes definitely cut that section off as that will change the resistance in the wire and could cause issues.

[ar15barrels]

The encoder head has 4 wires:

A black wire

A green wire

An orange wire

A white wire that has some red striping on it

Probe at the wires with a multimeter and see if you find DC voltage across the black and the white/red.
If you do, figure out where those go first.
The TTL wires can be hooked up either way, but will likely only work correctly when hooked up correctly.
You will just get funky DRO readings with the TTL quadrature wires reversed.

[kcstott]

Probe at the wires with a multimeter and see if you find DC voltage across the black and the white/red.
If you do, figure out where those go first.
The TTL wires can be hooked up either way, but will likely only work correctly when hooked up correctly.
You will just get funky DRO readings with the TTL quadrature wires reversed.

What Randall said

Jesus guys it's an encoder and they can be connected reversed thats how you change the CW/CCW ability to read. you just have to get the channels correct as Randell said or you will get either a lock up on the DRO or funky readings.
the voltages are so low that even if connected incorrectly all that will happen is an error. encoders are not that sensitive to misconnection.

Bauern had the wiring correct. on all encoders you have a ground and + VDC and then your channel outputs. More expensive and precise two channel encoders will have six wires. and that is just that the A And B channel has it's own + and - signal wire.

[ar15barrels]

More expensive and precise two channel encoders will have six wires. and that is just that the A And B channel has it's own + and - signal wire.

And that is just for noise rejection.
When you have two wires, one transitions to low at the same time that the other transitions to high.
Any noise created on the wires is cancelled out by the inverted signal of the other wire.

I spent 16yrs at a company that did motion control so this is fun stuff to play with...

[kcstott]

And that is just for noise rejection.
When you have two wires, one transitions to low at the same time that the other transitions to high.
Any noise created on the wires is cancelled out by the inverted signal of the other wire.

I spent 16yrs at a company that did motion control so this is fun stuff to play with...

Good to know because thats how all our encoders come.

Closed loop to a VFD on a hoist control. Fun stuff. You know I'm more a machinist then Electrician and motor control guy but this stuff is not that complex.
And I get paid more to be the Motor control trouble shooter then a machinist

[ar15barrels]

Good to know because thats how all our encoders come.

Closed loop to a VFD on a hoist control. Fun stuff. You know I'm more a machinist then Electrician and motor control guy but this stuff is not that complex.
And I get paid more to be the Motor control trouble shooter then a machinist

You can substitute a 6 wire encoder into a 4 wire system by simply ignoring the two inverted output ttl lines and only hooking up the standard ttl output lines.

[kcstott]

You can substitute a 6 wire encoder into a 4 wire system by simply ignoring the two inverted output ttl lines and only hooking up the standard ttl output lines.

another good thing to know.

Thanks buddy