Tree Journeyman 320 B Retrofit

[erikjgreen]

Well, I'm not an expert, but I can tell you what I'm doing on my mill.

For the inhibit, I'm basically doing what you describe. EMC2 has an "enable" output that it will switch on when it's in a "powered up" state. This disengages (or will) my relay, which ties the servo amps' inhibit to ground, thus enabling them. There's a note on the Mesa card manual that says to use a snubber diode with the relay to avoid spikes getting to the I/O card.

I'm also going to run the drive fault inputs into the Mesa card. I'll put in some settings (ladder logic, I think?) to make Emc2 ignore the fault input when its power switch is transitioning to "on" if that's a problem.

Dunno on grounding... I do run all items in the cabinet to a common ground, except where I'm grounding to an amp or I/O card pin, those I run to the ground pin on the circuit board in question.

Erik

[samco]

We have contactors in front of all equipment that gets shut down during an e-stop. You can see here the older 3 phase relays in the lower left hand corner of the box.

http://electronicsam.com/images/Kand...ctricalbox.jpg

Be gentle... We almost didn't have enough room...

These are in the estop loop with OT limits. (hard wired - the N.C. estop and limit switches are part of the loop) So when the estop is pressed (or over travel) - things shut down instantly. (the relay over current and vfd Error contact is also in the loop.)

I am using e-stop example 4 here LinuxCNC Documentation Wiki: Sample HAL And ClassicLadder

It works great for me.

So - in linuxcnc when I pull the estop out - hydraulic pumps start up and vfd and servo drive transformer is activated. Then when the 'on' button is pressed in emc - the servo drives are enabled (and the y axis brake is disabled). (among other things like a solinoid that enables hydraulic pressure to everything.)

[will gilmore]

Thanks for the input guys. After looking at your setups I think I'm pretty clear on the estop/limits/etc set up. There are existing relays on the machine for this purpose. I'm going to use a separate contactor to open the AC supply to the servo PS and to connect the servo braking resistors because the drives/ps are in a separate compartment of the electronics cabinet.

How about this: eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices 24VDC coil, 20A 2 NO, 2 NC contacts

EDIT: Here is the info from the ebay auction so people can learn from Al's post below after the auction is gone.

Up for sale is a brand new never used SH4 positive guided relay from AEG.
Unit comes in its original box.
Specs:
Part# SH4.22-NSW
Contacts: Rated 20 Amps
2 Normally open, and 2 Normally closed poles
Coil: 24Vdc
Positive guided design, assures that no normally open contact can close before any normally closed contact can open. Per IEC947-5-1 requirements.
UL/ CSA/ CE approved.
Dimensions: 1 3/4" W x 3 1/16" H x 2 7/8" D

[Al_The_Man]

That contactor relay has Force-Guided contacts which essentially makes it a safety relay that is the basic design of all safety relays where they are mandatory, so that one has a bit of an edge over the normal contactor.
BTW, the E-stop string should NEVER be a result of PLC logic, the mandatory code is always hardwired logic, with the end result being preferably a Safety Relay.
Al.

[samco]

Agreed. My estop loop is hardwired. The plc logic just allows emc to see and reset the loop. (once the loop is complete again)

sam

the E-stop string should NEVER be a result of PLC logic, the mandatory code is always hardwired logic, with the end result being preferably a Safety Relay.
Al.

[will gilmore]

The wiring continues...

Quick question. The AMC drives have +REF IN and -REF IN as the analog inputs. The 7i48 has AOUT0 as the analog output (with GND0 next to it). The 7i48 manual says:

ANALOG OUTPUTS
The analog output of the 7I48 swings from -10 v to +10V. Positive outputs are
generated when PWM+ is input is driven, and negative outputs when PWM- is driven. A
50 % duty cycle PWM signal will generate a 5V output. This mode of operation require the
PWM generator be set for "up/down" mode. Due to power supply limitations, The 7I48 has
limited DC output drive capability and should not have loads of less than 3K Ohms on its
analog outputs. (~24 mA maximum total +-10v current). To avoid power supply damage,
do no short more than one analog output at once.

How do I hook this up?

[Al_The_Man]

AOUT0 - +REF
GND0 - -REF
The AOUT0 swings from +10 to -10 WRT to GND0
Al.

[will gilmore]

Thanks. That's what I assumed but you know what they say.

[will gilmore]

I started wiring the amp connectors to the MESA 7i48. These are the encoder and REF wires. The connectors also have the home switches.

There are two shield wires on each connector for example Y2PL pins 13 and 14 which don't look like they were connected to the original controller. What should I do with them?

[Al_The_Man]

13 & 14 look like they carried the drain wire or shield through the connector?
Do your encoder wires have shields? If they come into the CPC connectors, you would normally terminate these with wires to the common ground point.
Al.

[will gilmore]

I cant tell if the wires have shields because they are inside conduits and jackets. Looking at the wiring diagram it looks like 13 and 14 are connected to the shields. I'll wire the shields together near the amp connectors and then one bigger wire to the main ground point?

[Al_The_Man]

That should work if you don't have a pin to continue them through the CPC connectors, as long as they anchor to ground or even the chassis point.
Al.

[will gilmore]

Hi Everyone,

Work has been busy and I haven't spent any time on the mill retrofit in the last month.

I'm still struggling with the enable for the servo amps. Here are the relevant parts of the manuals:

b30a8 servo drive manual:

TTL level (+5 V) inhibit/enable input. Leave open to enable drive. Pull to ground to inhibit drive. Inhibit turns off all power devices.

7i48 manual:

Each 7I48 channel has a OPTO-isolated transistor output that can be used to
enable external amplifiers. All six outputs are on when both input enable signals are low,
that is all enable outputs are switched at once. Maximum switched voltage is 36VDC.
Maximum output current is 10 mA. Even though all outputs are switched in common, they
are all isolated to allow different enable connections on a per amplifier basis.
Example connections:
1. Active high 12V amplifier enable on ch 0:
Connect ENA0+ to +12V source
Connect ENA0- to amplifier enable input
2. Active low TTL input
Connect ENA2- to ground
Connect ENA2+ to amplifier enable input

I talked to AMC tech support and they confirmed that it is the J1 jumper I need to remove to invert the inhibit logic of the drive. If I invert the logic open will be disabled and I can have the 7i48 pull the inhibit pin to ground to enable. Any tips on surface mount jumper removal? (see picture in post 79)

[erikjgreen]

That looks like a surface mount resistor in the pic, not a jumper.

If it's meant to be able to be changed, then there should be a plastic jumper you can pull/set with a pair of tweezers, and it won't require desoldering.

Unless I misunderstand my electronics terminology however, can't you just connect one side of the 7i48 card's pins to ground and the other to the servo amp enable pin? Wouldn't the card then close that connection when it flips the enable output to "on", attaching the servo amp pin to ground?

I may be wrong, it's been hard to wrap my head around how Mesa's output pins work.

Erik

[will gilmore]

Hi Erik,

It is basically a surface mount resistor with a resistance of 0. I think previous models of this drive had the plastic jumper you describe but they went to this probably so they can use a pick and place machine.

As I understand it the current inhibit logic needs an + or open to enable and - to disable. I think I could use a biggish resistor to pull the inhibit pin to ground and then use the mesa board to pull it high to enable. This may actually be a good option instead of trying my hand at surface mount desoldering.

[Al_The_Man]

Yes it is just a 'Resistor link' with 0 ohms, I have just use a soldering iron to lift it off the board, or if gentle you can snip it with small wire snippers.
According to how I interpret the 7148 instructions it works with either logic, but it is poorly explained.
The normal default for the AMC is open is enabled, it is taken to common to disable.
Al.

[erikjgreen]

Ah, okay.

I've removed SMDs in the past with a little soldering iron heat. Typically SMDs are installed with a paste solder, which has a little lower melting point than the coil stuff.

You could probably just touch both ends with an iron and lift it off. I'd recommend avoiding it though. Maybe use an inverter TTL chip on a separate board?

Erik

[will gilmore]

I emailed Peter at Mesa for advice on how to configure / wire the enable circuit.

[samco]

IIRC all of our amps have the jumper installed... Going from memory then - a +5 v on the inhibit pin would enable the drives. (because they where inhibit with the line above or 'inhibit - not')

Again - going from memory...

[will gilmore]

Samco - I dont understand. I think there is an internal pullup on the inhibit pin so open or +5VDC to enable and 0VDC to disable.

More questions:

There are 4 pins on the 7i48 that connect to the drive:
ENA0-
ENA0+
GND0
AOUT0

On the drive these are the pins I think I need to use
4 +REF IN
5 -REF IN
8 CURR MONITOR OUT (I may use this later)
9 INHIBIT IN
11 GND
16 FAULT OUT

Two questions:
1) I'm pretty sure GND0 --> -REF IN and AOUT --> +REF IN
Where does the GND on the drive connect to?

2) Fault monitoring. I want to add circuitry so that a fault in one of the drives (FAULT OUT goes to +5VDC) opens the estop chain which will be +24VDC. Al mentioned using a ULN2803 IC anyone have info on that or a different solution.