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Author Topic: USB or ModBus communication  (Read 3892 times)

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Offline JR

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USB or ModBus communication
« on: January 15, 2008, 05:23:44 PM »
Has anyone written a general plugin for USB communication or ModBus with more than one slave that can be used for various hardware ?
Re: USB or ModBus communication
« Reply #1 on: January 15, 2008, 11:11:58 PM »
Hi John,

For Modbus, it is sort of there. Under the serial modbus configuration, you can set up a schedule for the reads and writes to your various Modbus devices. Have a look at the SerialPlugModbus video tutorial at;

http://www.machsupport.com/Videos/Mach3%20Video%20Selections/Mach3%20Video%20Selections.html

Once that is done, you will then need to process the data depending on what you want to do.

To achieve that, you could write a macropump, or 1 or more Brains, or both. There are video tutorials for both of these methods.

What is it that you are tring to do?

Cheers,

Peter.
----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com

Offline poppabear

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Re: USB or ModBus communication
« Reply #2 on: January 16, 2008, 04:05:42 PM »
On serial you can write to multiple devices on a 485 network using slave device IDs
On Ether you can do the same, if al the devices have ether and can use your mach comp as the gateway, again you will need to be able to use device numbering.
If you want to use Modbus on a USB physical medium, you would have to get a converter that will convert serial to USB, (NOTE: sometimes it is a crap shoot to find converters that will not screw up the data, often you have to slow down your speed because of the conversion overhead).
You can also Daisy chain, i.e. you can go out to a "Master PLC or device" and then that device controls and talks to all your other devices, thus Mach only sees the Master device. I did this with 2 PLC's, I did Ethernet to my 1st PLC, then from that PLC a 422 to a second PLC the master PLC did all the I/O transactions with the 2cd and then it passes all the I/O to Mach.

Scott
Commercial Mach3 & Mach 4, Design/Build/Retrofit CNC and Industrial machines.
http://www.ss-systems-llc.com/
Re: USB or ModBus communication
« Reply #3 on: January 14, 2009, 04:25:12 PM »
If you want to use Modbus on a USB physical medium, you would have to get a converter that will convert serial to USB, (NOTE: sometimes it is a crap shoot to find converters that will not screw up the data, often you have to slow down your speed because of the conversion overhead).

Scott - What USB to 485 "dongles" have you had good luck with?  If not USB, what would you recommend for PC to 485 interface?
Re: USB or ModBus communication
« Reply #4 on: January 14, 2009, 06:22:40 PM »
If you want to use Modbus on a USB physical medium, you would have to get a converter that will convert serial to USB, (NOTE: sometimes it is a crap shoot to find converters that will not screw up the data, often you have to slow down your speed because of the conversion overhead).

Scott - What USB to 485 "dongles" have you had good luck with?  If not USB, what would you recommend for PC to 485 interface?


Hi,

The one I use and recommended to Scott is
http://www.dontronics-shop.com/usb-comi-single-port-usb-to-rs422-rs485-serial-adapter.html

I've had good success with it. I'm sure you could sources it in the USA if necessary.

Cheers,

Peter.
----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com

Offline JR

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Re: USB or ModBus communication
« Reply #5 on: September 01, 2009, 02:40:03 PM »
Found a work around.....
must add an ADDITIONAL... DoOEMButton (1021) Reset into one of my VB scripts.....
This then syncs the logic with the Brain Control