setting up Moeller VFD to chinese spindle

**ecat** · 19-09-2010

The DV51 manual I'm looking at online says the RJ45 port is RS485, ie it won't work when connected to a PC serial port without a RS232 to RS485 adapter. No biggie, easy enough to find, probably quite easy to make and I'm sure I've seen a USB type serial port that talked 485. I'll hunt something out if you need.

Of course if your DV51 is RS232 or you already have the 'special' cable then you should ignore this, lol.

Page 73, table 20...
RJ54 pin 5 : Send/receive, positive data channel
RJ54 pin 6 : Send/receive, negative data channel

... half duplex differential 5 volts

This one uses the Modbus protocol so you need to ensure the device IDs are set, unless there is a broadcast address which makes things easy :)

RE: Siemens manuals, you should take a look at their automation software + manuals some day :(

Edit:
The manual I'm looking at, lots and lots to read on communications http://www.inverter.co.uk/applications/manuals&datasheets/moeller-dv51-manual.pdf

**routercnc** · 20-09-2010

Hi Irving, Ecat,

I just saw the picture in the manual (same as your link ecat), plugged a standard network cable into the RJ45 socket on the VFD and removed my internet cable from my PC and plugged the other end in there. When it didn't work I just left it as it's not vital. However, looking back at the manual it does go on to explain a bit more, so its a case of RTFM !

Will look into an RS485 interface card and decide whether to bother for now, but thanks for your help.

**ecat** · 20-09-2010

Nice try :)

This is the Siemens way
http://uk.rs-online.com/web/search/s...28&cm_vc=av_uk

or for us mortals
http://uk.rs-online.com/web/search/s...13&cm_vc=av_uk

or directly
http://cgi.ebay.co.uk/USB-RS485-Inte...item1e5e3a2454
http://www.robot-electronics.co.uk/h...rs485_tech.htm

NB. I've only tried the Siemens device

**routercnc** · 20-09-2010

Thanks for that info. Does anyone make a convertor with an RJ45 female socket in, so that the RJ45 cable from the VFD can be plugged into that?

So the chain would be:
VFD > RJ45 cable > [female RJ45 in / convertor box / cable out] > RS485 PCI card in PC.

Otherwise, it seems a bit messy. Using the £16.99 RS solution with the block terminals it would seem that I have to strip out one end of the RJ45 cable, and connect the 2 signal pins. Is that correct?

Also the manual states that resistors are required at each end of the cable, with an note on watching the impedances. Do these solutions above include that feature already?

**ecat** · 20-09-2010

Originally Posted by routercnc

Thanks for that info. Does anyone make a convertor with an RJ45 female socket in, so that the RJ45 cable from the VFD can be plugged into that?

So the chain would be:
VFD > RJ45 cable > [female RJ45 in / convertor box / cable out] > RS485 PCI card in PC.

Otherwise, it seems a bit messy. Using the £16.99 RS solution with the block terminals it would seem that I have to strip out one end of the RJ45 cable, and connect the 2 signal pins. Is that correct?

Also the manual states that resistors are required at each end of the cable, with an note on watching the impedances. Do these solutions above include that feature already?

I'm sure you'll find something with a RJ45 socket, may put up the cost. The word 'industrial' means multiply by x where x is between 2 and 10.

How good is your soldering ?
http://www.rapidonline.com/Cables-Co...on-jacks/63744

from what I can tell this is a simple socket, it's certainly cheap. Watch out for cat5 sockets that contain additional components, inductors etc

An RS485 installation should ideally have a resistor at each end of the cable run, you can chain multiple devices over quite a distance, this minimises problems with reflections. Are these resistors necessary for a short run? I can't say for sure, you may get away with one or even none at all. It's worth getting a couple just in case but I see the dv51 lacks a switchable internal resistor - probably a feature on the deluxe model (!!) - so some cable hacking will be necessary to fit a resistor at that end.

**John S** · 20-09-2010

I have to ask Why ?

You have one inverter that's now running and no more in the pipeline ?

When we used to fit them on the machines we were offered the option of downloading the parameters but to be honest by the time you had gone in and altered 6 or 7 whilst you were testing it really saved no time over getting a laptop, finding the leads etc. and still having to test it.

**routercnc** · 20-09-2010

Hi John,

It's a fair question. I'm new to VFD drives, as you can tell, and when I saw this connection option I wanted to see what was involved. I suspect that I'll probably leave it configured as it is, but if it turned out to need lots of initial tuning then I wanted to know what my options were.

So the answer is because I could, and I'm inquisitive, although I'm not planning to at the moment.

Hi ecat,
Nice info thanks. If I go down this route I think you've covered it for me.

Great stuff, thanks
Barry