external devices connected to a CNC machine

[sinha_nsit]

Kindly bear with me as I am trying to learn interfacing of CNC machines with external devices. I am not even sure if I am asking sensible questions:

What external devices can be connected to a CNC machine?

Are the PMC signals (the so-called, interface signals) passed on to some external relay through an external PLC, or the PMC can directly drive the relay?

Similarly, how are input signals sent to the PMC?

Is the hardware connection through the RS-232C port of the CNC?

Any other relevant information?

Thanks in advance.

[Geof]

This link will give you information about connecting Haas rotary tables to other machines.

http://www.haascnc.com/customer_serv...ry/96-0315.pdf

[sinha_nsit]

Thanks.
But the link does not connect.

[Al_The_Man]

I assume you are talking Fanuc?
The communication between the CNC and PMC (PLC) is over an inernal bus called the BMI, Basic Machine Interface.
G registers are used to pass info from PMC to CNC such as operator panel commands, and F Registers are used to pass info from CNC to PMC such as M,S,T codes etc.
The PMC operates like any typical PLC as to programming and I/O.
The results of the PLC logic can be monitored in the on screen Ladder display.
Al.

[dcoupar]

It worked for me. It's a big pdf and slow to load, but it worked.

[sinha_nsit]

Originally Posted by Al_The_Man I assume you are talking Fanuc? The communication between the CNC and PMC (PLC) is over an inernal bus called the BMI, Basic Machine Interface. G registers are used to pass info from PMC to CNC such as operator panel commands, and F Registers are used to pass info from CNC to PMC such as M,S,T codes etc. The PMC operates like any typical PLC as to programming and I/O. The results of the PLC logic can be monitored in the on screen Ladder display. Al.

Thanks.
Yes, I am talking with reference to Fanuc, in terms of system variables for interface signals.
A more specific question (I am not sure if I am not talking non-sense):
Can we operate an external relay through PMC, by sending appropriate signal to the PMC through a macro?
For example, let us assume, I want that when the part count is 100, an external siren be automatically sounded. Is it possible?
Additionally, I may want the part count to be displayed on an external display board. Possible?

[Al_The_Man]

I don't normally get involved in part programming so there may be a function for that, I cannot recall seeing one however.
If it is possible, you may have to change the ladder logic however?
Someone like Dan Fritz may know.
Al.

[sinha_nsit]

Originally Posted by Al_The_Man Someone like Dan Fritz may know. Al.

Can you please pass on the request to Dan Fritz.
The problem is that there is no book which I can refer to. Fanuc manual also does not explain properly. How to learn then? There are many things which have to be learnt from others only.

[Dan Fritz]

There are two ways to output data from the part program, which does not involve the PMC or the ladder at all. You can connect an external device to the Fanuc's serial port, then output data to that device using macro commands, like this:

POPEN (opens the serial port)
DPRNT[HELLO] (sends the word "HELLO" to the external device)
PCLOS (closes the serial port)

DPRNT statements can send any text, or any variables to the external device. This would be the best way to connect an external display board. If the display board could accept serial data, you could display a "live count" of the number of parts like this:


O1234 (BEGINNING OF PROGRAM)
#501 = #501 + 1 (INCREMENT COUNTER VARIABLE)
N1
N2 (your program data)
N3
POPEN
DPRNT[#501]
PCLOS
M30

Using a variable in the 500 range makes sense here because the count would remain even if you powered off/on the machine. The operator could manually reset #501 to zero in MDI mode to reset the counter, or you could reset it in the program

Outputting a logic signal to a relay, or to a series of relays) can be done with the user macro output signals. Not all machines have the user macro outputs wired to a terminal strip, so you may have to seek out these signal points on an I/O board connector. Use the Fanuc CONNECTING manual for this. Each model Fanuc control will be a bit different in this regard.

There are 16 macro output signals and 16 macro input signals. You can read the inputs with a macro statement, and you can output a relay signal with a macro statement. The inputs are called UI0 through UI15 and the outputs are called UO0 through U015. They each correspond to a macro variable in the 1000 range. See your Fanuc operator's manual for more details on how to send data to these outputs. Basically, you can turn on an individual signal with a statement like:

#1100 = 1 (turns on relay UO0)
#1101 = 1 (turns on relay UO1)
#1100 = 0 (turns off relay UO0)
(etc.)

To send a 16-bit binary number using all 16 relays, you can assign a value to variable #1132. The binary equivalent of that number will be output on the 16 relays UO0-UO15.

Reading an input signal is a matter of just looking at the variables #1000 - #1015. These variables correspond to inputs UI0 - UI15. Reading macro variable #1032 gives you the binary value of all 16 inputs.

[sinha_nsit]

Thanks Dan.
I have understood quite a few things.
Please explain a few points a little bit more. Only you have the answer. I know that if someone very knowledgeable is asked "trivial" questions, he gets irritated. So, kindly bear with me.

The Connection manual which I have, uses X for input and Y for output. I could not find UI0-UI15 and UO0-UO15. It is still not clear to me where the output signals (#1100 series) go, and how these operate an external relay. Similarly, how can we sense the ON/OFF state of an external sensor such as a limit switch? We may want to take some decision based on this information.

What I have understood is, RS-232C port of the CNC machine is not for this purpose. One has to directly connect the external relay / sensor to I/O board of PMC. Are there terminals on I/O board with UI0-UI15 and UO0-UO15 designations?

I also believe that PMC does not have relay outputs. It can only give source type DC outputs. So, external devices cannot be AC type.

Please throw some light on this. It will be a great help.

Thanks for your patience, and looking forward to hear from you.

Sinha

[Dan Fritz]

You must be looking at the connecting manual that only describes the PMC functions, not the "Hardware" connecting manual. On some of the newer controls, Fanuc publishes two types of connection manuals. All the User Macro inputs and outputs are processed by the PMC, but usually they are just passed through to some corresponding hardware inputs and outputs. If your machine's ladder does not include these signals, then maybe your machine tool builder never anticipated their use and left them out.

The type of input is usually +24vdc. Outputs can be one of several types, depending on the model of CNC control and the I/O board you have. Older Fanuc 5, 6, and 7 models had IC reed relays (contact closures). Later controls had a +24vdc voltage output. Some Fanuc I/O boards also have "open collector" outputs where the signal is pulled to ground when it's on. You've never mentioned what model control and what I/O board you have.

If you need to connect AC devices, I suggest you connect a solid-state relay to the Fanuc output, and use that to drive your AC device.

If you tell me the model control, maybe one of the forum members can send you the correct hardware connection manual.

The RS232 port on the Fanuc can be used for any purpose you like. We've connected indexers that accept RS232 commands, we've connected computers to collect touch-probe data for digitizing, we've tied in DNC systems with barcode readers, and we've attached printers for collecting probing data. I'm sure other forum members have done lots of imaginative things with the serial ports as well. You asked about a "Display board", and I was thinking of a display board with a serial input. That would certainly be possible.

Generally speaking, you will need to use the serial port to pass DATA to another device, and you can use the User Macro signals to pass digital (on/off) or binary or BCD data to another device.

[sinha_nsit]

My control is 0i Mate TC.
Any comment specific to this model?