Re: [Emc-users] Modbus wiring

On Monday 04 April 2016 09:37:08 Nicklas Karlsson wrote: > > Maybe. OTOH, I can probably knock up something in eagle or geda/pcb, > > and carve it on my machine by the time UPS could make a drop here. > > Those pictured boards Farnell shows me are quite simple, and adding > > another thru-hole

Re: [Emc-users] Modbus wiring

> Maybe. OTOH, I can probably knock up something in eagle or geda/pcb, and > carve it on my machine by the time UPS could make a drop here. Those > pictured boards Farnell shows me are quite simple, and adding another > thru-hole for the supply bypassing those chips ought to have would be >

Re: [Emc-users] Modbus wiring

On Monday 04 April 2016 01:52:42 Nicklas Karlsson wrote: > > > > > ISO7421 > > > > > > > > Now thats sweet, and a heck of a lot better thought out than the > > > > last such chip I looked at a decade ago. Needs a 4 wire cable > > > > from each direction, but I don't see as that as a problem

Re: [Emc-users] Modbus wiring

Lemme clarify- whether or not you're galvanically isolating, any RS485 transceiver needs either 3-wire or 4-wire logic due to its half-duplex nature, OR to be protocol-aware. I don't know if the RTS could be used that way. RTS is hardware flow control, which is obsolete now and often not

Re: [Emc-users] Modbus wiring

> That's a bare unidirectional isolator. OK for RS232. Problem being, > Modbus is over RS422/RS485, a bidirectional protocol and there's a lot > of difficult problems in creating buffers of any sort. It doesn't know > which direction it's supposed to drive at any given time. > >

Re: [Emc-users] Modbus wiring

That's a bare unidirectional isolator. OK for RS232. Problem being, Modbus is over RS422/RS485, a bidirectional protocol and there's a lot of difficult problems in creating buffers of any sort. It doesn't know which direction it's supposed to drive at any given time.

Re: [Emc-users] Modbus wiring

> > > > ISO7421 > > > > > > Now thats sweet, and a heck of a lot better thought out than the > > > last such chip I looked at a decade ago. Needs a 4 wire cable from > > > each direction, but I don't see as that as a problem other than > > > stealing the ground and 3.3 or 5 volts to run its side

Re: [Emc-users] Modbus wiring

On Sunday 03 April 2016 18:12:28 Nicklas Karlsson wrote: > > > ISO7421 > > > > Now thats sweet, and a heck of a lot better thought out than the > > last such chip I looked at a decade ago. Needs a 4 wire cable from > > each direction, but I don't see as that as a problem other than > > stealing

Re: [Emc-users] Modbus wiring

> > ISO7421 > > Now thats sweet, and a heck of a lot better thought out than the last > such chip I looked at a decade ago. Needs a 4 wire cable from each > direction, but I don't see as that as a problem other than stealing the > ground and 3.3 or 5 volts to run its side of it at both ends.

Re: [Emc-users] Modbus wiring

On Sunday 03 April 2016 15:07:59 Nicklas Karlsson wrote: > ISO7421 Now thats sweet, and a heck of a lot better thought out than the last such chip I looked at a decade ago. Needs a 4 wire cable from each direction, but I don't see as that as a problem other than stealing the ground and 3.3

Re: [Emc-users] Modbus wiring

ISO7421 is two channel bidirectional, there are more of them with different configurations. On Sun, 3 Apr 2016 14:30:50 -0400 Gene Heskett wrote: > On Sunday 03 April 2016 14:10:04 Nicklas Karlsson wrote: > > > I tried opto isolators and they did not work without errors

Re: [Emc-users] Modbus wiring

On Sunday 03 April 2016 14:10:04 Nicklas Karlsson wrote: > I tried opto isolators and they did not work without errors while > capacitive insulation barriers did. It was a suprise and I can't tell > why. I think most devices including opto have a limited dv/dt > tolerance. Damn, old wet ram

Re: [Emc-users] Modbus wiring

On Sunday 03 April 2016 13:36:23 Danny Miller wrote: > Well, if you have 2 differential wires with a simple optoisolator at > the far end, ground noise/ground loops would have no effect > whatsoever. You don't need a ground. There would be no place to put a > ground. There are no common-mode

Re: [Emc-users] Modbus wiring

I tried opto isolators and they did not work without errors while capacitive insulation barriers did. It was a suprise and I can't tell why. I think most devices including opto have a limited dv/dt tolerance. On Sun, 3 Apr 2016 12:36:23 -0500 Danny Miller wrote: >

Re: [Emc-users] Modbus wiring

On Sunday 03 April 2016 09:35:04 Nicklas Karlsson wrote: [huge snip] > You could also read if there is something in the manual about a > shielded cable and how it should be connected. > > > Nicklas Karlsson Such information is not mentioned in my Chinglish manual. And thats troublesome too

Re: [Emc-users] Modbus wiring

Well, if you have 2 differential wires with a simple optoisolator at the far end, ground noise/ground loops would have no effect whatsoever. You don't need a ground. There would be no place to put a ground. There are no common-mode issues. The slave device's ground could be +300VDC above

Re: [Emc-users] Modbus wiring

> > Gene Heskett wrote: > > > On Saturday 02 April 2016 07:04:14 Nicklas Karlsson wrote: > > > > > I had SERIOUS problems with my X200 VFD and RS485 bus- I > > > > > "mostly" fixed it. > > > > > > > > > > Here's the thing- yes, RS485 is differential, but the VFD is > > > > >

Re: [Emc-users] Modbus wiring

On Sunday 03 April 2016 06:21:38 Nicklas Karlsson wrote: > On Sat, 2 Apr 2016 11:34:25 -0400 > > Gene Heskett wrote: > > On Saturday 02 April 2016 07:04:14 Nicklas Karlsson wrote: > > > > I had SERIOUS problems with my X200 VFD and RS485 bus- I > > > > "mostly" fixed it. > > >

Re: [Emc-users] Modbus wiring

On Sat, 2 Apr 2016 11:34:25 -0400 Gene Heskett wrote: > On Saturday 02 April 2016 07:04:14 Nicklas Karlsson wrote: > > > > I had SERIOUS problems with my X200 VFD and RS485 bus- I "mostly" > > > fixed it. > > > > > > Here's the thing- yes, RS485 is differential, but the VFD

Re: [Emc-users] Modbus wiring

On Saturday 02 April 2016 07:04:14 Nicklas Karlsson wrote: > > I had SERIOUS problems with my X200 VFD and RS485 bus- I "mostly" > > fixed it. > > > > Here's the thing- yes, RS485 is differential, but the VFD is > > probably NOT opto-isolated input. Differential conveys strong noise > >

Re: [Emc-users] Modbus wiring

> I had SERIOUS problems with my X200 VFD and RS485 bus- I "mostly" fixed it. > > Here's the thing- yes, RS485 is differential, but the VFD is probably > NOT opto-isolated input. Differential conveys strong noise immunity- > but ONLY when both A and B wires' voltages are within the input range

Re: [Emc-users] Modbus wiring

I had SERIOUS problems with my X200 VFD and RS485 bus- I "mostly" fixed it. Here's the thing- yes, RS485 is differential, but the VFD is probably NOT opto-isolated input. Differential conveys strong noise immunity- but ONLY when both A and B wires' voltages are within the input range of the

Re: [Emc-users] Modbus wiring

On Friday 01 April 2016 17:17:16 John Thornton wrote: > You're going to turn copper to steel? > Puzzled me too John, until I remembered the date. Today I don't believe a thing I read, and only about 5% of what I see. > On 4/1/2016 3:57 PM, Nicklas Karlsson wrote: > >> On 1 April 2016 at 20:07,

Re: [Emc-users] Modbus wiring

I can turn gold to lead, do you want see. It should have been that kind of steal. > You're going to turn copper to steel? > > On 4/1/2016 3:57 PM, Nicklas Karlsson wrote: > >> On 1 April 2016 at 20:07, Dave Cole wrote: > >>> Profibus is basically an RS485 network as

Re: [Emc-users] Modbus wiring

On 4/1/2016 1:48 PM, andy pugh wrote: > On 1 April 2016 at 20:07, Dave Cole wrote: >> Profibus is basically an RS485 network as well.I have no idea why >> they used a purple jacket color. > There is an awful lot of purple wiring on the London Underground. > Perhaps

Re: [Emc-users] Modbus wiring

You're going to turn copper to steel? On 4/1/2016 3:57 PM, Nicklas Karlsson wrote: >> On 1 April 2016 at 20:07, Dave Cole wrote: >>> Profibus is basically an RS485 network as well.I have no idea why >>> they used a purple jacket color. >> There is an awful lot of

Re: [Emc-users] Modbus wiring

> On 1 April 2016 at 20:07, Dave Cole wrote: > > Profibus is basically an RS485 network as well.I have no idea why > > they used a purple jacket color. > > There is an awful lot of purple wiring on the London Underground. > Perhaps that is data cable. What do you

Re: [Emc-users] Modbus wiring

On Friday 01 April 2016 13:58:55 Stephen Dubovsky wrote: > You can not include the termination or pull up/down resistors on a > RS422/485 network in the drivers (unless they can by disabled.) You > don't know where (or how many) are located on the bus. They are > multi-drop networks after all.

Re: [Emc-users] Modbus wiring

Well that is true. It does tend to stand out from the generic gray control cabling. Dave On 4/1/2016 1:26 PM, Peter Blodow wrote: > ... because this will be different from all other kinds of cables. > Imagine large facilities, dozens of buildings, with thousands of devices > being controlled

Re: [Emc-users] Modbus wiring

On 1 April 2016 at 20:07, Dave Cole wrote: > Profibus is basically an RS485 network as well.I have no idea why > they used a purple jacket color. There is an awful lot of purple wiring on the London Underground. Perhaps that is data cable. -- atp "A motorcycle is a

Re: [Emc-users] Modbus wiring

... because this will be different from all other kinds of cables. Imagine large facilities, dozens of buildings, with thousands of devices being controlled by a central control room, wired by random cable colours. These are being mixed with current supply, LAN, telephone and all other cables

Re: [Emc-users] Modbus wiring

On 4/1/2016 11:55 AM, andy pugh wrote: > On 1 April 2016 at 18:33, Dave Cole wrote: >> Unless you are running at 60+ Kbaud and up and long distances you likely >> won't need anything but twisted pair cabling. > It was mainly the purple thing. Ha ha... Well, I must like

Re: [Emc-users] Modbus wiring

Yes termination with pull up/down in both ends. On Fri, 1 Apr 2016 13:58:55 -0400 Stephen Dubovsky wrote: > You can not include the termination or pull up/down resistors on a > RS422/485 network in the drivers (unless they can by disabled.) You don't > know where (or how

Re: [Emc-users] Modbus wiring

You can not include the termination or pull up/down resistors on a RS422/485 network in the drivers (unless they can by disabled.) You don't know where (or how many) are located on the bus. They are multi-drop networks after all. Only terminate the two far ends. On Fri, Apr 1, 2016 at 1:37

Re: [Emc-users] Modbus wiring

> > > Twisted pair is a transmission line and subject to all the vagaries > > > of load matching and such. > > > > > > That cables impedance is not listed there, > > > > Yes it is. 120 Ohms. > > Resistance is NOT impedance, Andy. And I first read that as 1200 because > my screen is high res and

Re: [Emc-users] Modbus wiring

On 1 April 2016 at 16:58, John Dammeyer wrote: > Which cable is the Van Damme? > Can you post an ebay # or link? http://www.ebay.co.uk/itm/141838984494 -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical

Re: [Emc-users] Modbus wiring

On Friday 01 April 2016 11:33:18 andy pugh wrote: > On 1 April 2016 at 16:22, Gene Heskett wrote: > >> http://www.rapidonline.com/cables-connectors/belden-9841-data-cable > >>-for-rs-485-51-6887 > > > > Twisted pair is a transmission line and subject to all the vagaries > > of

Re: [Emc-users] Modbus wiring

On 1 April 2016 at 18:33, Dave Cole wrote: > Unless you are running at 60+ Kbaud and up and long distances you likely > won't need anything but twisted pair cabling. It was mainly the purple thing. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is

Re: [Emc-users] Modbus wiring

On 4/1/2016 10:33 AM, andy pugh wrote: > On 1 April 2016 at 16:22, Gene Heskett wrote: >>> http://www.rapidonline.com/cables-connectors/belden-9841-data-cable-for-rs-485-51-6887 >> Twisted pair is a transmission line and subject to all the vagaries of >> load matching and such.

Re: [Emc-users] Modbus wiring

Which cable is the Van Damme? Can you post an ebay # or link? Thanks John > -Original Message- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: April-01-16 8:33 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Modbus wiring > > On 1 Apri

Re: [Emc-users] Modbus wiring

On 1 April 2016 at 16:22, Gene Heskett wrote: >> http://www.rapidonline.com/cables-connectors/belden-9841-data-cable-for-rs-485-51-6887 > > Twisted pair is a transmission line and subject to all the vagaries of > load matching and such. > > That cables impedance is not listed

Re: [Emc-users] Modbus wiring

On Friday 01 April 2016 07:02:14 andy pugh wrote: > On 1 April 2016 at 11:46, Erik Christiansen wrote: > > Incidentally, is that cable in the last picture twisted pair? > > Shielded or no, is its characteristic impedance controlled? > > It is just what I cold find in

Re: [Emc-users] Modbus wiring

On Friday 01 April 2016 06:46:02 Erik Christiansen wrote: > On 30.03.16 17:13, andy pugh wrote: > > In the end, I fitted a different VFD which has a pre-written HAL > > driver. It also only has two connections for RS485, so is less > > confusing. I found a way to connect the dongle to the

Re: [Emc-users] Modbus wiring

On 1 April 2016 at 11:46, Erik Christiansen wrote: > > Incidentally, is that cable in the last picture twisted pair? Shielded > or no, is its characteristic impedance controlled? It is just what I cold find in Maplin that evening. I will see how well it works, and if

Re: [Emc-users] Modbus wiring

On 30.03.16 17:13, andy pugh wrote: > In the end, I fitted a different VFD which has a pre-written HAL driver. > It also only has two connections for RS485, so is less confusing. > I found a way to connect the dongle to the motherboard header: >

Re: [Emc-users] Modbus wiring

On 9 February 2016 at 11:23, andy pugh wrote: > This is where things get iffy. Imagine that I have the 2-terminal > dongle plugged into a laptop. What do I use for a gnd? Stuff a wire > down the side of the USB connector? trap the wire in the hinge? :-) In the end, I fitted a

Re: [Emc-users] Modbus wiring

On 9 February 2016 at 09:10, Erik Christiansen wrote: > What about 20 mA current loop? Sending an analogue signal as a current, > rather than a voltage is reputed to be significantly more noise immune > than sending it as a voltage. I have a 7i49 with 6 channels of +/-

Re: [Emc-users] Modbus wiring

On 08.02.16 13:16, andy pugh wrote: > I need to connect to 8P8C connector on the VFD which has pins > 1 A' > 2 B' > 3 A' > 4 R > 5 D > 6 B' > 7 DP5V > 8 SG(GND) > > Is that ever going to work? The YSB dongle seems deficient in > terminals by at least 1, possibly 4... The above looks a lot like

Re: [Emc-users] Modbus wiring

On 9 February 2016 at 09:10, Erik Christiansen wrote: > The two-terminal dongle would be used for half-duplex, with separate > grounds, relying on less than 7v float. This is where things get iffy. Imagine that I have the 2-terminal dongle plugged into a laptop. What do

Re: [Emc-users] Modbus wiring

On 08/02/16 13:16, andy pugh wrote: > Is that ever going to work? The YSB dongle seems deficient in > terminals by at least 1, possibly 4... The quick answer here is YES the dongle is deficient in that it should provide at least a screen connection rather than just data. The adapter I use with

Re: [Emc-users] Modbus wiring

On 09.02.16 11:23, andy pugh wrote: > On 9 February 2016 at 09:10, Erik Christiansen > wrote: > > The two-terminal dongle would be used for half-duplex, with separate > > grounds, relying on less than 7v float. > > This is where things get iffy. Imagine that I have the

Re: [Emc-users] Modbus wiring

andy pugh" <bodge...@gmail.com> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Monday, February 8, 2016 7:22:17 PM Subject: Re: [Emc-users] Modbus wiring On 8 February 2016 at 23:10, Bertho Stultiens <ber...@vagrearg.org> wrote:

Re: [Emc-users] Modbus wiring

On 09/02/16 05:20, Kirk Wallace wrote: > (Bottom of page here: > http://wiki.linuxcnc.org/cgi-bin/wiki.pl?AVR > has it been five years already?) Sounds about right ... must get some of these longer term projects finished ;) That includes a nice modbus module for additional inputs and control ...

Re: [Emc-users] Modbus wiring

On 2/8/2016 3:54 PM, andy pugh wrote: > On 8 February 2016 at 20:34, Bertho Stultiens wrote: >> But, I should not hijack the thread with information theory... > In theory Modbus should be better, but I don't have any information > about the VFD interface. > > That's the

Re: [Emc-users] Modbus wiring

On 02/08/2016 12:54 PM, andy pugh wrote: > On 8 February 2016 at 20:34, Bertho Stultiens wrote: >> But, I should not hijack the thread with information theory... > > In theory Modbus should be better, but I don't have any information > about the VFD interface. > > That's the

[Emc-users] Modbus wiring

I am tempted to attempt to control the lathe VFD with Modbus. I have one of these: http://www.ebay.com/itm/CH340-USB-to-RS485-485-Converter-Adapter-Module-For-Win7-Linux-XP-Vista-/201258967189?hash=item2edbf82095:g:SDAAAOSw2s1UrPYd I need to connect to 8P8C connector on the VFD which has pins 1

Re: [Emc-users] Modbus wiring

yea it's a bit short on pins i use these http://www.ebay.co.uk/itm/Useful-80mm-USB-2-0-to-RS-485-RS-422-Serial-Converter-Adapter-Cable-ST-/151912461839 On 8 February 2016 at 13:16, andy pugh wrote: > I am tempted to attempt to control the lathe VFD with Modbus. > > I have

Re: [Emc-users] Modbus wiring

On 2/8/2016 12:51 PM, andy pugh wrote: > On 8 February 2016 at 17:40, Dave Cole wrote: >> RS485 is two wire, half duplex. >> I think you have a RS422 connection that can run full duplex. >> I don't recognize the D and R pins??Perhaps Data Ready and Request >> to Send

Re: [Emc-users] Modbus wiring

RS485 is two wire, half duplex. I think you have a RS422 connection that can run full duplex. I don't recognize the D and R pins??Perhaps Data Ready and Request to Send ?? Those aren't normally required for RS422. Dave On 2/8/2016 8:16 AM, andy pugh wrote: > I am tempted to attempt to

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 17:40, Dave Cole wrote: > RS485 is two wire, half duplex. > I think you have a RS422 connection that can run full duplex. > I don't recognize the D and R pins??Perhaps Data Ready and Request > to Send ?? > Those aren't normally required for

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 20:34, Bertho Stultiens wrote: > But, I should not hijack the thread with information theory... In theory Modbus should be better, but I don't have any information about the VFD interface. That's the version of information theory that matters to me

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 21:04, Bertho Stultiens wrote: > I thought that ModBus was pretty standardized: So which register do I write to to set output frequency? Which register do I read to monitor motor current? (And, back to the original question, how do I wire the 8 pins

Re: [Emc-users] Modbus wiring

Bertho, I agree with the sentiment that it is less than ideal to have something that certainly has a local microprocessor that then creates an analog out which you then read in. It's a lossy channel and subject to any number of problems. That assumes you have the software skills and documentation

Re: [Emc-users] Modbus wiring

On Mon, 8 Feb 2016 11:23:23 -0800 Jerry Scharf wrote: > Bertho, > > I agree with the sentiment that it is less than ideal to have something > that certainly has a local microprocessor that then creates an analog out > which you then read in. It's a lossy channel and subject

Re: [Emc-users] Modbus wiring

On 02/08/2016 09:01 PM, Nicklas Karlsson wrote: >> I agree with the sentiment that it is less than ideal to have something >> that certainly has a local microprocessor that then creates an analog out >> which you then read in. It's a lossy channel and subject to any number of >> problems. That

Re: [Emc-users] Modbus wiring

> On 02/08/2016 08:52 PM, Nicklas Karlsson wrote: > >> Noise in analog will reduce the effective resolution, whereas noise in > >> digital can be easily filtered and the resolution stays constant. > >> Analog signals cannot be isolated easily and trying so results in > >> awkward non-linearities

Re: [Emc-users] Modbus wiring

On 02/08/2016 09:54 PM, andy pugh wrote: > On 8 February 2016 at 20:34, Bertho Stultiens wrote: >> But, I should not hijack the thread with information theory... > In theory Modbus should be better, but I don't have any information > about the VFD interface. > > That's the

Re: [Emc-users] Modbus wiring

On 02/08/2016 09:12 PM, Peter C. Wallace wrote: >> The number of bits required goes to the root of Shannon's information >> theory. We see how effective it is in our daily life everywhere and it >> is better than analog. >> >> Telephony has been digitalized completely today. Television has >>

Re: [Emc-users] Modbus wiring

On 02/08/2016 10:12 PM, andy pugh wrote: >> I thought that ModBus was pretty standardized: > So which register do I write to to set output frequency? Do you have the original documentation of the VFD? I guess not. Do you have any "old" VFD control or test software, If you have, you can reverse

Re: [Emc-users] Modbus wiring

> On 8 February 2016 at 17:40, Dave Cole wrote: > > RS485 is two wire, half duplex. > > I think you have a RS422 connection that can run full duplex. > > I don't recognize the D and R pins??Perhaps Data Ready and Request > > to Send ?? > > Those aren't normally

Re: [Emc-users] Modbus wiring

On 02/08/2016 07:01 PM, Dave Cole wrote: >>> RS485 is two wire, half duplex. >>> I think you have a RS422 connection that can run full duplex. >>> I don't recognize the D and R pins??Perhaps Data Ready and Request >>> to Send ?? >>> Those aren't normally required for RS422. >> I am becoming

Re: [Emc-users] Modbus wiring

On 02/08/2016 08:52 PM, Nicklas Karlsson wrote: >> Noise in analog will reduce the effective resolution, whereas noise in >> digital can be easily filtered and the resolution stays constant. >> Analog signals cannot be isolated easily and trying so results in >> awkward non-linearities that need

Re: [Emc-users] Modbus wiring

On 02/08/2016 08:23 PM, Jerry Scharf wrote: > I agree with the sentiment that it is less than ideal to have something > that certainly has a local microprocessor that then creates an analog out > which you then read in. It's a lossy channel and subject to any number of > problems. That assumes you

Re: [Emc-users] Modbus wiring

er (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Modbus wiring > > On 02/08/2016 08:52 PM, Nicklas Karlsson wrote: >>> Noise in analog will reduce the effective resolution, whereas noise in >>> digital can be easily filtered and the resol

Re: [Emc-users] Modbus wiring

> On 02/08/2016 07:01 PM, Dave Cole wrote: > >>> RS485 is two wire, half duplex. > >>> I think you have a RS422 connection that can run full duplex. > >>> I don't recognize the D and R pins??Perhaps Data Ready and Request > >>> to Send ?? > >>> Those aren't normally required for RS422. > >> I

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 21:42, Bertho Stultiens wrote: > Try and try again, or get a hold of the documentation. ;-) The documentation is silent on the subject:

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 22:20, Bertho Stultiens wrote: > My best guess is that they have mapped the entire register space from > the front-panel config (page 4-9 and forward), as documented, to the > communications register map. That should be possible to test with a few >

Re: [Emc-users] Modbus wiring

On 02/08/2016 11:03 PM, andy pugh wrote: >> Try and try again, or get a hold of the documentation. ;-) > > The documentation is silent on the subject: > http://www.lovatoelectric.com/Single-phase-supply-200-240VAC-50-60Hz-EMC-suppressor-built-in-PNP-24VDC-programmable-inputs/150005010/spd

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 23:10, Bertho Stultiens wrote: >> I thought of that, but they only document writable parameters. None of >> them look like a likely place to read currents or voltages. > > Often you have r/w registers, where you read a measured value and write > a

Re: [Emc-users] Modbus wiring

On 8 February 2016 at 23:10, Bertho Stultiens wrote: > I'd start with writing the manufacturer for the right docs. I tried. http://www.lovatoelectric.co.uk/Information-request/cnt Appears to have a "Send" button that doesn't do anything. -- atp If you can't fix it, you

Re: [Emc-users] Modbus wiring

On 02/08/2016 11:56 PM, andy pugh wrote: >> My best guess is that they have mapped the entire register space from >> the front-panel config (page 4-9 and forward), as documented, to the >> communications register map. That should be possible to test with a few >> read commands. > > I thought of

Re: [Emc-users] Modbus wiring

Andy, This isn't the worst thing I've seen. Rs485 is a two wire differential half duplex signalling system. The doc says that it can run up to 38.4kbps. So you one 1 wire to the plus of the master and the vfd and the other wire to the minus. It will run on anything twisted that is better than

Re: [Emc-users] Modbus wiring

On 2/8/2016 1:03 PM, Bertho Stultiens wrote: > Telephony has been digitalized completely today. Television has > transitioned from analog to digital, freeing more than 50% of the > bandwidth, while increasing the number of channels. Radio will follow > (currently running parallel). There have