forum.cncdrive.com

i have been putzing around with the plugins, mainly the modbus and modbusez trying to get the spindle to work with the uccnc/rs485/windows system , .. rs485 2 wire setup, for the life of me i can not get anything to talk.
im using the AC tech scf series vfd

http://www.actechdrives.com/PDF/AC-Tech/AC-Tech-SCF-Drives-Installation-Operation-Manual.pdf

the other important info:

http://download.lenze.com/TD/SF__SCF%20modbus%20guide__v7-0__EN.pdf

anyone have a similar setup and can share the modbus settings? can be any plugin .

Hi Tracar,

Brief look at your manual you posted states any register is +1 for Modbus register.

Register for on/off command is 01 Hex so use 02

bits in hex are as follows:

stop = 0004
forward start = 0088
reverse start = 0044

Register for frequency(speed/rpm) is 40(28 hex) so try 41 = 0029

You will also need to set parameters in VFD for serial communication and use 1 for Modbus address.

If you have anymore questions please post in the ModbusEZ plugin thread in plugin section of this forum.

Dan

tracar wrote:i have been putzing around with the plugins, mainly the modbus and modbusez trying to get the spindle to work with the uccnc/rs485/windows system , .. rs485 2 wire setup, for the life of me i can not get anything to talk.
im using the AC tech scf series vfd

http://www.actechdrives.com/PDF/AC-Tech/AC-Tech-SCF-Drives-Installation-Operation-Manual.pdf

the other important info:

http://download.lenze.com/TD/SF__SCF%20modbus%20guide__v7-0__EN.pdf

anyone have a similar setup and can share the modbus settings? can be any plugin .

I don't have that VFD but control mine (Bosch Rexroth EFC5610) via the UCCNC built in Modbus plugin, so I can't really help and test this, just quickly looking through your manuals...

Describe what you have done so far, what works and what not as well as what sort of RS485 hardware are you using to connect it to your PC. Whatever you are using, it must be configured eqally on the PC end as it is on the VFD end, so you must set up the PC serial port AND the VFD (#15) for 9600 bps, no parity, two stop bits (9600,N,2). If those don't match you will not be able to establish connection.

Also be aware that "two wire setup" in reality means three wires because in most cases you also need a shield. It can work with only two, but not reliably, so a twisted pair shielded cable is recommended.

Note also that your driver has some sort of locking security (#48) which must be disabled. It seems that the VFD has some strange locking/unlocking mechanism, which must be set after each power up or communication timeout. At least that's my understanding of page 26 (7.2).

Be aware also that there is a watchdog timer, so if you have enabled that in #15 then you must make sure that the VFD is polled (constantly sent data to) at least every 5 seconds, otherwise the VFD will stop after 10 seconds. I don't know if Modbuez is polling or not, but the Modbus pluging which is built into the UCCNC does poll.

I am not sure that you can send the start command as one word which includes both direction of rotation and the actual start command. On page 11 and 12 it seems like you have to split it into two messages since the note on the top of page 12 says: "During each write to Register #1 only one bit should be set in the drive control word." and on the page before the example says: "To start the drive send 0008H." which does not include the direction bit. It seems that the direction bit must be set before.

Otherwise it seems pretty straight forward, there is an example on page 26 (7.3) which should be pretty easy to configure in UCCNC and I guess also in Modbusez.

thanks for the info. it will help me alot to understand the stuff, i will have a look at the machine on the weekend. but first to build a rotary phase converter