i have a mill working with mach3 and it has a toolchanger working with A/B plc via modbus on com1 i was wondering if it is possible to connect a peter homann modio on com2 
thanks in advance
jekran

Hi,

No you can't use 2 com ports in Mach3 with Modbus.

What you can do is use RS485 to talk to the PLC and the ModIO through a single com port. This is how most talk to multiple modbus devices.

The ModIO can use RS232, RS485 two wire, or RS485 four wire.

You can also use the ModIO as a RS232 to RS485 converter as well.

Does your PLC haave a RS485 port?

Hi,

No you can't use 2 com ports in Mach3 with Modbus.

What you can do is use RS485 to talk to the PLC and the ModIO through a single com port. This is how most talk to multiple modbus devices.

The ModIO can use RS232, RS485 two wire, or RS485 four wire.

You can also use the ModIO as a RS232 to RS485 converter as well.

Does your PLC haave a RS485 port?

yes the plc has a rs485 port
my intention is to leave the plc doing the atc stuff and then i would like to have a modio to controll the mpg,analog feed rate, start the spindle and controll it via analog 0-10v i would like to have the mpg handheld
do i need another port on the pc with rs485 port cause as far as i know the serial port cannot be a rs485?

You have 2 options here.

1.  Use an RS232 to RS485 converter and run the PLC and the ModIO off that.
2. Use the RS232 to RS485 on the ModIO and run the PLC off the ModIO's RS485 connectors.

Have a look at these 2 engineering notes;
http://www.homanndesigns.com/EN007-MC01R1.pdf
http://www.homanndesigns.com/EN007-MA02R1.pdf

Cheers,


Peter.

You have 2 options here.

1.  Use an RS232 to RS485 converter and run the PLC and the ModIO off that.
2. Use the RS232 to RS485 on the ModIO and run the PLC off the ModIO's RS485 connectors.

Have a look at these 2 engineering notes;
http://www.homanndesigns.com/EN007-MC01R1.pdf
http://www.homanndesigns.com/EN007-MA02R1.pdf

Cheers,


Peter.

which one do you think i should use ?

If the ModIO is in a handheld pendant, use a separate RS232 to RS485 converter. If the ModIO is mounted into a CNC controller box then use the ModIO's onboard RS232 to RS485 converter.


If you are putting the ModIO into a handheld pendant as you stated earlier, it would not be very efficient to have the RS232 commms from the computer run up to the ModIO, get converted to RS485 and be sent back down the cable, then to the PLC.

Cheers,


Peter.