Mesa 7i76ED to AB Ultra 3000 I/O

I'm hooking up my U3K servo drive and could use some guidance.

In addition to the step/dir connections, I need three LCNC outputs (drive inputs), and two LCNC inputs (drive outputs).

My plan was to use opto isolated relays - LCNC outputs trigger some relays (drive inputs on contacts), and the drive triggers a couple more relays for the Mesa inputs.

However, this seems a little kludgy.  Problem is that I'm struggling with the diagrams in the manual and can't quite figure out how to connect the I/O to my 7i76ED (sinking outputs) directly.

It looks like the drive has sourcing outputs...but I'm not sure.  If I could just connect a drive output to a 7i76ed input and connect IOCOM to Mesa Vin- that'd be nice.

Also not sure about triggering the drive inputs with the mesa outputs...

Anyone want to take a stab at this?  Manual diagram pages attached.

Thx,
R

The relevant information is actually in the 4 pages before the one from the document you have attached.

#1: First you need to provide I/O power: This need to be from a 10.8v to 26.4v PSU. Easiest way for this is to use the same power supply used for the 7i76 I/O. Connect the 24V+ (positive) to IOPWR pin of the Ultra 3000 (pins 29 and/or 30). 24V- (negative) goes to IOCOM pin(s).

#2: Yes, the drive is definitively sourcing outputs and sinking inputs. The outputs will supply 0v (Off state) or V IOPWR (On state), meaning the same voltage connected to the IOPWR pin.
The inputs will turn on with V IOPWR applied to it. Load is 3 to 12 ma. See manual page 2-29 for more info.

#3 Sinking output (from 7i76) will NOT work directly with the sinking input of the drive. A simple pull up resistor could be used in most cases. See here: knowledge.ni.com/KnowledgeArticleDetails...00000YI7ICAW&l=en-US

#4 Yeah, the diagrams are confusing. Just understand that the right side (on the right of the dotted line) is the Ultra 3000 internals, thus is always the same. The left side is then just a variation of the possible type of inputs. But note that all of them are sourcing...

Here is what I think should work for the pull-up resistor:

Connect a 470 ohm resistor between the IOPWR pin (+24V) and the input you want to use on the drive. Next make sure that the input is turned on by doing this (via ultraware). If not you will need a lower resistor but this could be a problem since this will draw more current from the 7i77. A 470 ohm resistor @24 V will draw about 51ma, well within 7i76 spec.

Once done connect the (sinking) output of the 7i76 to the input of the drive (do not remove the resistor).
Activating the output should result in an OFF state for the input, while deactivating the output will result in an ON state. Note that logic is inverted.

JPL wrote:

The relevant information is actually in the 4 pages before the one from the document you have attached.

#1: First you need to provide I/O power: This need to be from a 10.8v to 26.4v PSU. Easiest way for this is to use the same power supply used for the 7i76 I/O. Connect the 24V+ (positive) to IOPWR pin of the Ultra 3000 (pins 29 and/or 30). 24V- (negative) goes to IOCOM pin(s).


 

Drive Inputs
The u3K input diagrams all appear to indicate that IOPWR already has 24v+ and is (or can be) used to trigger the drive inputs.  i.e. connect IOPWR to a drive input and that input goes HIGH.

But what you're saying is that IOPWR needs to be supplied with 24v from the Mesa power supply... This doesn't make sense to me - I was under the impression that IOPWR was the drive's internal 24v supply for use with IO.  That is, I power the drive with 240vac, and the drive's internal AC-DC PSU creates 24vdc for use with the IO.

Or is this what was cryptically discussed in the 'aux 5v logic supply' section for maintaining logic power when AC is shut off?  What if I don't care about maintaining logic power?
Going back over the diagrams, I think figure 2.20 on pg. 2-31 shows your suggestion:

• IOPWR => drive input (through resistor)
• Mesa output => drive input
• Mesa Vin- => IOCOM
• Adjust resistor to highest value which still triggers input (to reduce load on Mesa)

Drive Outputs
Just to be clear...drive output to mesa input, and IOCOM to Mesa Vin-?

Sorry to be dense, just don't want to let the smoke out and while the AB manuals are generally comprehensive... this part isn't clicking for me.

Thanks, 
R

Yes, IOPWR need to be supplied via an external PSU. It is clearly mentioned on page 2-26 of the installation manual: "All Ultra3000 drives require an isolated external 12-24V power supply for proper operation of the digital I/O" .Then, on the diagram just below it is written: "Voltage range of the external power supply for proper operation of the digital I/O" -> "10.8 to 26.4v" . But this could be the same power supply used for the field I/O of the 7i76.  

I have worked with those drives for many years and are still using them. If you're still unsure just check the voltage with a voltmeter directly on the drive between IOPWR and IOCOMM. With some (1k) resistor between the two you should get about 0v without an external power supply connected. (NOTE: Be extra cautious with the encoders inputs (CN2) those are the most sensitive)

Drive outputs:
"drive outputs to mesa input, and IOCOM to Mesa Vin-"  --> YES

Drive inputs:
Yes, diagram 2-20 is basically what I would suggest but again, IOPWR must be connected to V+ too. The maximum resistance I would try is about 1k, anything higher would probably not work because of the relatively low resistance of the input circuit of the u3000.  (2.7k series + 1k parallel to the led according to the diagram)

  


 



 

Again, thank you.

For some reason, this manual makes me feel dumb despite it not being a poor English translation.

Edit - OMG, it just dawned on me why they've got two IOPWR and IOCOM terminals.  One for external 24v power supply, and another one to connect (the same) 24v to field components & I/O.

Jeez I've been dense.

Just to be thorough:

While the IOPWR need to be supplied with an external power supply, the encoders (main and auxiliary) power is supplied internally  (YES that can be confusing)

DO NOT apply any voltage to the "Auxiliary encoder power out" (CN1 pin 1) or "Encoder power" (CN2 pin 14). Those are 5V supplied by the internal power source of the drive. Also, DO NOT connect the ECOM pins CN1 pin 1  AND CN2 pin 6, those are the encoders common pin, to the external PSU common.

 

No plans on using the aux encoder terminals in or out.  And CN2 is going straight to my motor encoder - that one already works (through ultraware).

Nope, just needed a couple I/O for enable, follwer enable, drive fault, start homing, etc.