just in case you didn't know...

[SCzEngrgGroup]

I'm using a foot pedal that has a mechanical "push to unlock" lever which prevents the foot pedal from being activated accidentally (or, at least it makes it much less likely). Of course, this lock wouldn't help in a scenario of absentmindedly activating the switch when the spindle is running. SCzEngrgGroup's suggestion sounds like a possible solution to that issue.

McMaster-Carr


Good to know! I think I'll (eventually) incorporate this into my own design.

My PDB has multiple interlocks to make it near impossible for the PDB to cause damage to the machine or risk harm to the user. Not only is PDB operation bi-directionally interlocked to the VFD (the PDB cannot be activated if the spindle is active, nor can the spindle be activated if the PDB is active). This is done directly in hardware. There are also multiple firmware interlocks that prevent PDB activation any time the spindle is turning, even if simply spun by hand. Even in the (exceedingly unlikely) event of multiple hardware failures causing false activation of the PDB, the spindle will be immediately turned off, the instant the PDB mechanism moves from it's inactive position. The firmware is also written in such a way that it would be all but impossible even for a firmware execution error or "crash" to activate the PDB.

Safety is not something to be trifled with. I find it incredible that Tormach apparently did not provide any safety interlocks at all. Were a user to be injured due to an improper PDB activation, they'd be in world of hurt from a legal standpoint.

Regards,
Ray L.

[anglin]

I mentioned this in a different thread, but thought it might be worth sharing here too. I finished my power draw bar installation today and included the spindle interlock while I was doing it. I recorded video of the installation to show what is involved in the modification:

[tbaker2500]

Nice, thanks for the vid!

[hjl4]

Tormach fail!!!!!!!!!!

Yikes, what kind of engineering is that. That would of been the first thing I would of implemented before even offering a PDB to my customers. So simple and yet they overlooked it(or chose to ignore).

[tmarks11]

I find it incredible that Tormach apparently did not provide any safety interlocks at all.

From the posts above, it sounds like implementation is somewhat haphazard, probably implemented at different stages of development, and not uniformly back fitted. Looks like Series 1 has none, Series III (purchased after June 2011, just a guess) cuts power to the spindle when you actuate the PDB, Series III with ATC does it right and disables PDB function when the spindle is turning (and I am assuming disables the ATC, since it would do those forks no good to try to pick up a 5000 rpm tool).

I connected the VFD Interconnect as described in the ATC Operators Manual, and to no great surprise, it works.
If I press the PDB button while the spindle is running it doesn't respond.

Also sounds like the customer service representative is talking BS when he said that type of interlock doesn't exist. I have found CS in many businesses making stuff up when they don't have the answer. Unfortunate, but there it is. The proof is that there are different versions of an interlock installed, yet the CS rep said there was none. I suspect the rest of the CS rep statement is also nonsense, where he claimed to have tested it, and not hurt anything. Right.

Sounds like it is time for Tormach to issue a service bulletin, since (like Ray said) adding this is child's play, since the capability is already built into almost every VFD built (using an aux contact relay, triggered by whatever you program the VFD to do).

That beings said, nothing prevents you from grabbing a moving spindle (on this or a manual machine), or starting the machine with the drawbar wrench in place (also hazardous to your health); it is like a tablesaw or circular saw, easy to kill or injury yourself by doing it wrong, yet manufacturers have managed for decades to avoid serious lawsuits. The courts seem to believe that the individual who uses tools like this is accepting some risk. Different story if used in a commercial business where OSHA rules apply. I don't think they would approve of a tormach there at all, missing some required "safety" features (that many people work hard to defeat when they buy other machines).

[popspipes]

I have the 1100 series 3. I know mine locks out. I even double checked it this morning. As long as the spindle turns the PDB is locked out both the foot pedal and the hand switch. It also locks out in manual if the spindle is turning.

It will lock out on machines with the ATC, I only have the PDB and it didnt lock out, I needed the phone cable that comes with the ATC, and they wouldnt sell me one of them as a part, with this cable it will work.

I did mine a bit different, using a separate 24 volt relay connected to the VFD output contact, then used this as an interlock with the 12 vdc supply to the VFD.
This works the same, just a different approach to the problem.

[TurboStep]

...I suspect the rest of the CS rep statement is also nonsense, where he claimed to have tested it, and not hurt anything. Right...

I don't recall reading that the CS rep claimed to have tested this. I which post was that reported?
Step

[tmarks11]

I don't recall reading that the CS rep claimed to have tested this. I which post was that reported?
Step

Right here:

...Talked to Tormach, and sure enough there is no interlock on the Pdb....Tormach says they fail test this scenario and the machine survives just fine, but the tooling is another matter.

[TurboStep]

Right here:

Thanks, I thought you were referring to them testing the interlock - not testing without the interlock!
In which case this is tested and approved behaviour, so when the Tormach dismantles itself at 5000 RPM this still isn't "Outside of the Scope of Intended Use"

I find it sad that someone went to the trouble of building this feature onto the PDB control board specifically for this purpose, it's even labeled "VFD interconnect" in the installation manual, but the CS rep has no idea what it does - even says this feature doesn't exist.

I don't have a foot pedal and I can't see myself pressing the PDB button to remove a spinning tool - but it's been done - I'm leaving mine connected.
Step

[anglin]

I find it sad that someone went to the trouble of building this feature onto the PDB control board specifically for this purpose, it's even labeled "VFD interconnect" in the installation manual, but the CS rep has no idea what it does - even says this feature doesn't exist.

It's not labeled as the VFD Interconnect in the Tormach Power Draw Bar manual, just in the Tormach ATC manual.

[TurboStep]

It's not labeled as the VFD Interconnect in the Tormach Power Draw Bar manual, just in the Tormach ATC manual.

The CS rep should have been familiar with ALL of the manuals. After all, I found it: http://www.cnczone.com/forums/tormac...ml#post1459808 and I don't have the ATC.
Step

[tmarks11]

The CS rep should have been familiar with ALL of the manuals. After all, I found it: http://www.cnczone.com/forums/tormac...ml#post1459808 and I don't have the ATC.
Step

True, but even though Tormach is a machining-centric company, that doesn't mean their CS reps are machinists. If they were, they would be out making $25-50 per hour instead of $11 talking on the phone. Not everyone demonstrates extreme enthusiasm for their jobs, and makes themselves the expert in their field that they should be. Unfortunate, but as I said before: typical.

I have found CS in many businesses making stuff up when they don't have the answer. Unfortunate, but there it is.

At least Tormach has a group of people who answer the phones all the time, which makes them far above average in the niche that they fill.

Since Tormach would not sell the cables individually I built my own.

Tormach should. Think of the markup: $25 for a $3 RJ-11 "precision" phone cord.

[popspipes]

Couldn't wait, I just had to try it. I don't have a foot pedal but I expect that the behaviour would be the same with the hand controls. I have a series II + PDB (no ATC).
I removed the belt, started the motor and pressed the release button. The PDB released and the motor cut out and freewheeled to a stop i.e. without using the VFD breaking feature.
The VFD does however have a output to indicate when the motor is being powered. This appears to be used by the ATC which may be why some have reported that the PWB locks out when the spindle is running. Check out the Tormach document UM10081_TTS_ATC_PCNC1100_1212B.pdf. Page 8 shows a photo of the Power Drawbar Control Circuit board with the VFD interconnect on the right. Note the comment "If you purchased a Power Draw Bar before June, 2011, you may need to change the Power Draw Bar control circuit board." If I'm not mistaken, this should be connected directly to the VFD pins T1 (0V Common) and B3 (Digital output - Zero speed) as shown on page 11. I tested this output and it does indicate when the motor is being powered. The PWB control board has a small IC next to the connector which looks like an opto-isolator but I couldn't get a good enough view inside the housing to really confirm this.
I don't have this connection because I don't have the ATC. It would be very tempting to try it out, but then I ask myself why Tormach didn't simply supply a cable with the PDB if it really is this simple?
Step

They may include the phone cable thats needed now, kind of a safety hazzard without it. The relay I installed was after I burned up the chip on the board by plugging the connector into the wrong socket duh!! I did order a new board to put it back to original.......

This was another hole you pulled me out of Step!

thanks again.......

[dneisler]

I saw a post or video a long time ago about how to add this. It was a simple phone cord you plugged in to an existing port and somewhere else. Have to see if I can find it now.

[TurboStep]

I saw a post or video a long time ago about how to add this. It was a simple phone cord you plugged in to an existing port and somewhere else. Have to see if I can find it now.

Try this thread first

and then this one http://www.cnczone.com/forums/tormac...ml#post1455334
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