I am trying to interface a Teco SG2-20VR-D (user manual here:
http://www.bb-elec.com/bb-elec/literature/manuals/SG2PLR_UserManual_0707m.pdf and modbus manual here:
http://www.bb-elec.com/bb-elec/literature/manuals/SG2_V-typeModbusProtocol_0807.pdf) with Mach3.
Here is what I've done so far:
* Configured the unit to have slave address "02" using the "LAD Version 1.9" using the RS-232 interface (separate from 485)
* Installed 120ohm resistors on the 485 line
* Configured a USB to 485 adapter to COM6
* Under the "Modbus Confugration" screen, Port Num: 6, Baud Rate: 38400 8-2-N, Do NOT use RTS for transmit, Timout of 1500ms
* Click the "Test Modbus" button
* Port Num: 6 and Baud Rate: 38400, Slave Addr: 2, Start: 100 (hex), Num Regs:1, input registers
* Click "Open" and it responds "No error"
Here are my questions:
* Why is there no option for stop, parity and data bits on the "ModBus Serial Control Monitor" page?
* Why would you need to re-enter Port Number and Baud Rate again on the monitor page if it's on the Configuration page?
* What does the slider bar under Discrete Input(s) do?
* What is occuring when you click "Report Slave ID" and "Read Excp Stat" buttons? When clicking "Report Slave ID" mach3 returns "receive timeout".
* Why do I get "CRC Error" when I attempt to read?
* Is there a difference between slave address "1" and "01"?
* My PLC uses RTU, not ASCII - is Mach3 using RTU or ASCII? Is it configurable?
* Is there any simple way to peek at the data on the 485 serial line?
On a side note... I've watched the modbus videos and read everything I could find on the mach site with the word "modbus".
Thanks!