Mike,
Section 6.3 of the ModIO manual depicts the ModIO register addresses. To use both MPGs you need to be concerned with registers,
1150 - MPG1 Count
1155 - MPG2 Count
1156 - MPG Tick counter
In the Mogbus serial plugin configuration page, you need to set up a Modbus transaction that reads these 3 registers. The most efficient way to do this is to read 7 contiguous holding registers starting at register 1150. Read theses at a 25mS period rate.
Then in the Brain you need to;
1. get register 1150 (ENCODER1) and assign it to the Mach3 MPG1 count
2. get register 1155 (ENCODER2) and assign it to the Mach3 MPG2 count
3. get register 1156 (TICKCTR) and assign it to the Mach3 Tick count
In the brain, since you are reading 7 registers starting at address 1150, assuming you are using config 0 in the plugin
address 1150 is accessed as MOD:0-P:0
address 1155 is accessed as MOD:0-P:5
address 1156 is accessed as MOD:0-P:6
If this is not clear, look at the videos on setting up the Modbus serial plugin configs.
Also read through the article I wrote on using the ModIO with Brains and the serial Modbus plugin.
http://www.homanndesigns.com/pdfs/Using_Modbus_with_Mach3.pdfThe Brain needs to set;
address 1150 (MOD:0-P:0) to Mach3 Control variable 'MPG1 Count'
address 1155 (MOD:0-P:5) to Mach3 Control variable 'MPG2 Count'
address 1156 (MOD:0-P:6) to Mach3 Control variable 'MPG TickCount'
With it setup you should be able to see the MPG1&2 counts on the Mach3 diagnostic page change as you rorate the MPGs.
Also you need to use the Mach3 jog tab (accessed by pushing the tab key) to assign MPG1 to the X-axis and MPG2 to the Z-Axis, or visa versa.
Cheers,
Peter