CC-Link, Mitsubishi PLCs

[HCBFlash]

Oh-boy, What exactly IS CC-Link (and I don't mean what their website attempts to say)?

Isn't it really just a pseudo-standard for Mitsubishi's communication link between a melsec PLC CPU and a remote I/O rack?

Is it very close to any other networks?

Almost any insights would be helpful.

 

[ControlThis]

I've used a lot of CC-link. It is a fieldbus network proprietary to mitsubishi. You can comunicate lots of I/O or control lots of cc-link specifc components like servo amplifiers, vfd's, valves, encoders, etc.
In concept it's very close to competitors fieldbus networks but each is just different enough to be proprietary.
If you've ever hooked up a servo amplifer you know the interface or wiring can be complicated. With cc-link, all the I/O and comunication to the amp or vfd is over the same three wires.
I designed a system using cc-link that controls about 40 pneumatic solenoid valves, about 100 sensors and a VFD. The control cabinet is 50 feet from the machine. All that I/O is run to the cabinet over 3 conductors! A twisted 18/3 cable. A ton of saved wiring and cabinet space in this application.
CC-link has it's place. CC-link compatible components are made more and more available every day. Still Selection is limited compared to a filedbus network such as Allen Bradley's "Device Net" system, but you also pay a premium for Allen Bradley.
I like cc-link for applications I've tried. It's very fast and easy to set-up and operate once you go through the short learning curve. Also, once up and running it's very reliable. I've had no issues with any of the cc-link stuff I've commisioned. I'd say just as reliable as hard-wired stuff.
Hope this helped. Don't want to go on and on, so let me know if you have any more questions.
Good Luck!

 

[HCBFlash]

So moderate to large Mitsubishi VFDs have terminals for terminating the 3c shielded cable I presume, but for your solenoid application you had a small cabinet (12x16 kind-of) near the conventional devices each 2-wired to a remote I/O module? Wouldn't extra power be needed? ...or you're talking about very very small solenoids.

I've been led to believe that even solenoids might have direct cclink connection capability, but would that only be by wiring it to what would in essence be a communication module or "remote I/O" wired to a cclink module? If that is the case, you'd simply have a machine or line bristling with little "Hoffman boxes" wired to individual devices. Also an installation with so many communication modules (and network powered I/O points such as solenoids) would draw enough power from the comm line that boosters would be needed all over. We'd be talking about 24 or 48 VDC max and maybe 3A max power on the line too, wouldn't we?

I'm surprised to find that a 50' run would be economically feasible for this sort of application, although I realize that other factors could have overridden apparent $ for materials.

I've never worked with any individual devices connected directly to devicenet (or others), so I feel really clueless on this stuff.

 

[controlsdude]

I am curious, how is emergency stop wired for these devices?

Is this communications protocol have a built in safety estop like profisafe? Or do you have to bring out estop wire to disable the output for all these individual outputs?

To me wiring estop for distributed networks is the biggest problem.