Cable Length PDMX

[DocTanner]

I will be relocating my MechMate this year to a new shop.
I have the PDMX 122 breakout board. I prefer to leave the machine in it's current configuration. This will require a 20 foot (7 meter) cable. Will this work Or is the Ethernet Smoothstepper a better option?

Thanks,
DonRoss
AKA DocTanner

[Tom Ayres]

Depends on how far the drive is...Ha Ha :rolleyes: I think Pete is using 20' cables with his PMDX126, so I'd imagine it would be fine.

[Robert M]

DonRoss, I’m assuming your referring to the distance from your 122 BOB with a USB SmoothStepper and the computer?
If so, the best I can remember, with that kind of a setup ( BTW, It’s what I’m set up with and my SS is on top of my BOB, and the computer board sits in my controller box, +/- 12in apart !!)….the SS should be best when nearby to the computer board.
The shorter the better.
Search in this forum, it’s been covered a few yrs back, like…..+/- 4yr
R ;)

[pblackburn]

I have (2) 20 foot cables on mine. No problem with it. With an ethernet smooth stepper, it would be best to post at warp9 forum.

[Robert M]

DonRoss....& Pete

When I wrote " the best I can remember"....this is what I was referring to "see here (http://www.mechmate.com/forums/showthread.php?p=26144&postcount=1)"
Hope this helps & clears some !!
Later ;)

[KenC]

From Wikipedia

Cabling
A USB twisted pair, where the "Data +" and "Data −" conductors are twisted together in a double helix. The wires are enclosed in a further layer of shielding.

The data cables for USB 1.x and USB 2.x use a twisted pair to reduce noise and crosstalk. USB 3.0 cables contain twice as many wires as USB 2.x to support SuperSpeed data transmission, and are thus larger in diameter.[60]

The USB 1.1 Standard specifies that a standard cable can have a maximum length of 5 meters with devices operating at Full Speed (12 Mbit/s), and a maximum length of 3 meters with devices operating at Low Speed (1.5 Mbit/s).[61][62]

USB 2.0 provides for a maximum cable length of 5 meters for devices running at Hi Speed (480 Mbit/s). The primary reason for this limit is the maximum allowed round-trip delay of about 1.5 μs. If USB host commands are unanswered by the USB device within the allowed time, the host considers the command lost. When adding USB device response time, delays from the maximum number of hubs added to the delays from connecting cables, the maximum acceptable delay per cable amounts to 26 ns.[63] The USB 2.0 specification requires that cable delay be less than 5.2 ns per meter (192 000 km/s, which is close to the maximum achievable transmission speed for standard copper wire).

The USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification: for copper cabling with AWG 26 wires the maximum practical length is 3 meters (9.8 ft).[64]

[IMMark]

From Wikipedia

Cabling
A USB twisted pair, where the "Data +" and "Data −" conductors are twisted together in a double helix. The wires are enclosed in a further layer of shielding.

The data cables for USB 1.x and USB 2.x use a twisted pair to reduce noise and crosstalk. USB 3.0 cables contain twice as many wires as USB 2.x to support SuperSpeed data transmission, and are thus larger in diameter.[60]

The USB 1.1 Standard specifies that a standard cable can have a maximum length of 5 meters with devices operating at Full Speed (12 Mbit/s), and a maximum length of 3 meters with devices operating at Low Speed (1.5 Mbit/s).[61][62]

USB 2.0 provides for a maximum cable length of 5 meters for devices running at Hi Speed (480 Mbit/s). The primary reason for this limit is the maximum allowed round-trip delay of about 1.5 μs. If USB host commands are unanswered by the USB device within the allowed time, the host considers the command lost. When adding USB device response time, delays from the maximum number of hubs added to the delays from connecting cables, the maximum acceptable delay per cable amounts to 26 ns.[63] The USB 2.0 specification requires that cable delay be less than 5.2 ns per meter (192 000 km/s, which is close to the maximum achievable transmission speed for standard copper wire).

The USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification: for copper cabling with AWG 26 wires the maximum practical length is 3 meters (9.8 ft).[64]

Looks like the PMDX-122 connects via 26 pin ribbon cable or DB-25, so I don't know if the USB stats would apply?
Mark

[KenC]

AFAIK, twisted pair are better then flat ribbon in terms of noise.
Usually, everywhere I go, I read "u can use flat ribbon cable if it is for short connection of less then 2 ft".
AND, its not often you get long exposed ribbon cable come with commercial products.

[IMMark]

Yes, I think the shielded variety are "better" than the ribbon. The PMDX allows for both, but I was really referring to the DB-25. My understanding is (and this is not my area of expertise, and certainly not as it applies to the MM specifically) that the DB-25 can go to 30' and perhaps longer? Which I thought was almost double of the USB? (Which I don't think you can use with the PMDX-122)?
Again...no expert here for sure :)
Mark

[KenC]

For long LPT cable, its best to have IEEE1284 cable.
Non-compliance cable might work if noise is not a problem.
The longest non-compliance cable I use is 8meter length.

[IMMark]

I am sure you are correct sir...I couldn't disagree even if I wanted to...I have to use a converter program just to take meters to a length I understand :D
Mark

[pblackburn]

The ones I used are IEEE 1284 shielded cables.

[Tom Ayres]

Personally I think the 5 m serial cable is the way to go

[domino11]

I think Don was referring to a parallel cable for the 122 and going to an Ethernet smoothstepper only if the cable length was too long.

[IMMark]

That is what I thought too???

[pblackburn]

I will be relocating my MechMate this year to a new shop.
I have the PDMX 122 breakout board. I prefer to leave the machine in it's current configuration. This will require a 20 foot (7 meter) cable. Will this work Or is the Ethernet Smoothstepper a better option?

Thanks,
DonRoss
AKA DocTanner

I took it also as comparing 2 items:

1) a long length parallel cable of 20 feet
or
2) changeover to a cat5 or cat6 cable connected to a smooth stepper.

[DocTanner]

Thanks guys. I will try the longer cable first. If not I will go with the smoothstepper.
Thanks,
DonRoss
AKA DocTanner

[DocTanner]

A 25 foot IEEE 1284 shielded cable is what I ended up with.
No Problems so far.

Thanks,
DonRoss

[darren salyer]

Thanks for the update, good to know.
Post some pics of projects when you get the chance.