Hitachi VFD question

[Highpower]

Has anyone here made up their own extension cable for remote mounting the control head on a Hitachi SJ200 series VFD?

$75.00 seems a bit steep to me for a 3 foot Ethernet cable!

Just wondering if they are wired straight through, or in a twisted pair configuration.

[PeteM]

It's a standard cable. I've got mine on about a 3' extension, paying maybe $6 for the cable. Don't recall what Hitachi gave for the much higher price, but it may include an enclosure for the display? I ended up using a cast aluminum weather-tight outlet box and just fished the cable through 3/4" conduit.

[Forrest Addy]

Nah! You don't need no steenking Ethernet unles you're runnng the VFD fro a PLC or computer. If you wish to run three wires from a standard Start/Stop manual motor control station you need to connect them kinda like in the link below except you connect to the appropiate terminals on the VFD.

http://wiki.owwm.com/Default.aspx?Page=Motor%20Starter%20Wiring%20Diagrams&AspxAutoDetectCookieSupport=1

There should be directions and a circuit diagram in the Hitachi manual.

[Doozer]

Forrest-
He has the one where you can take the control panel with the display off.
Yea, I have seen where the switch polarity on some wires.
--Doozer

[Forrest Addy]

AH! I have one similar. I got a cable outfit to make me one 10 ft long. I think it cost $28 for the cable itself but it went along with some other work. So maybe I got a deal.

[Bguns]

Even though twisted pairs can shrug off some interference.

Multiconducter SHIELDED cable should be used for control wiring on a VFD...

RF getting into a VFD, could turn it on unexpectedly, or something equally not expected...

A common source of such wire, is simple CB/Radio microphone cable.

Only the end of shield, at VFD should be grounded, to prevent ground loops..

[Forrest Addy]

I've been down the road on control wiring on VFD's. I've come to think the best stuff is vinyl coated shielded comm wire with color coded, braind/foil shielded, plated, stranded #24 conductors. It works the best and simplest and the major houses will sell you cut pieces if you bring them a box of doughnut or ome other bribe.

When I was doing such things and wanted to protect the signal cable from harm, I slid it and a couple spare conductors and a ground in a piece of 3/8 rubber air hose with a strain relief cable. Make the termination so the wire was tight and solidly anchored and the signal cable had a little slack in it. I used the spare conductors for annunciator light power, whatever. The extra ground was for the frame of the control enclosure.

It wasn't forklift proof but it stood up to anythng a machinist could do out of negligence.

[Highpower]

It's a standard cable. I've got mine on about a 3' extension, paying maybe $6 for the cable. Don't recall what Hitachi gave for the much higher price, but it may include an enclosure for the display? I ended up using a cast aluminum weather-tight outlet box and just fished the cable through 3/4" conduit.

No enclosures included. $75.00 for a 1m length of cable.
Problem is, I can't see the wire colors on both ends to see how it's wired.

[Doozer]

Bguns- Highpower meant not a twisted pair, as in telephone cable or such, but reversed polarity. Some makers of proprietary cables switch around pins to make their patch cable unique. Sort of like using bastard screw threads. But yes, twisting comm wires does work to cancel out interference.
---Doozer
PS- Highpower $75?!?!? I feel ya.

[Highpower]

Bguns- Highpower meant not a twisted pair, as in telephone cable or such, but reversed polarity.

Yes! Thanks Doozer - bad phrasing on my part.

IIRC, a 'normal' Ethernet cable has the wires 'crossed' so that both ends have the same "polarity". In other words, looking at the ends of both RJ-45 connectors they would have the same wire positions.
[12345678] [12345678]

I have a feeling though, (based on how the display plugs into the front of the inverter) that this cable is wired 'straight through' and looks like this:
[12345678] [87654321]

Or possibly some odd arrangement all together? I was hoping somebody owned one of these cables that could give me the correct configuration.

Also I can understand the need for shielded cable if I was using the analog inputs for an external potentiometer - but all I want to do is remotely mount the digital control away from the inverter. Shielded cable still needed?

My first VFD -- so be gentle with me....

[Highpower]

It's a standard cable. I've got mine on about a 3' extension, paying maybe $6 for the cable.

Pete,
Does everything (LED's, display, etc.) function ok on your display?
Could you check the wiring of each plug on your cable?
Thanks.

[PeteM]

I've been using my 3hp SJ200 for about a year with the plain Ethernet extender. Haven't checked every possible function, but the display works properly, the speed control is fine, everything I've programmed seems to work as it should, the fault codes show up just fine, and haven't had any false starts or stops.

Cable was standard issue from a local electronics supply place. Now buried in conduit, so won't be interested in checking the polarity further. Judging from my experience, why not just buy a cheap cable and try it?

[Bguns]

If done properly, the digital inputs are probably optoisolated, and fairly RF resistant.

A digital remote sure costs more than than analog stuff... I can just put a piece of Lexan over front of my wall mounted vfd enclosure to see the VFD hz.

Knob and toggle switch on mill head = small and compact. Smaller than the remote heads...

No touchy membrane switches to fail either....

Mentioned twisted pair to keep things simple

[psomero]

by the EIA/TIA spec, all ethernet cable is always twisted pair.



you can get shielded cat5 and cat6. in addition with the fact that it's twisted pair, you can get pretty good signal integrity out of the stuff.



highpower: no need to see the colors to check the pinouts. just get some small solid core wire, then get a multimeter and probe each terminal on the rj45 connectors to test for continuity. if it's a real ethernet cable per EIA/TIA 586 A/B the pinouts can be found on wikipedia or whatnot and should have two pairs switched around in the middle.

[CountZero]

You can also get ethernet cable with each individual pair shielded.