energy meter

[vishalshinde885@gmail.com]

can anyone tell mi how to connect energy meter having port rs485 to labview. we have to aquire data from energy meter using modbus RTU

[Albert.Geven]

maybe interesting which energy meter you have?

Vendor and type and revision number e.g.

[DavidBoyd]

By any chance, is it an AccuEnergy Acuvim device?  They make some great single- and three-phase devices in a panel meter form factor, fittable with a wide range of transformers, and they're ModBus interfaced.

And I wrote LabVIEW drivers for them

Dave

[vishalshinde885@gmail.com]

thanks Albert...

     schnider conzerve energy meter (EM 6434).

 We are connecting this energy meter using modbus(RTU) .

For this we are using usb to RS485 converter .

connections are made like energy meter-USB to RS485 converter -pc(LabVIEW).

but we are getting some error (6101) timeout error.

we want to acquire current value which are stored in address 3929 (2 registers).

following are the attachments of screen shot of timeout error and vi we are using.

[vishalshinde885@gmail.com]

if there is hardware problem in usb to rs 485 how to identify it....???

[DavidBoyd]

I'm not familiar with the Schneider/Conserv devices, but glancing at their manual they appear similar to the ones I referred to above.  The code you posted seems reasonable as a starting point.

One item to check for is the "wire mode" of your RS-485 converter.  From the manual, it's clear that the physical wiring is two-wire, half-duplex.  Converters and their serial drivers vary somewhat, but you *may* need to ensure:

Wire the converter's Tx+ to Rx+, and its Tx- to Rx-, then wire the resultant pair to the meter.  Most converters I've encountered don't internally bridge their transmitter and receiver just because you set them for a two-wire operating mode.

Ensure the Windows driver is configured for two-wire mode, sometimes called "TxAuto" or similar.  This is the mode that causes the serial driver to turn off the transmitter when not actively sending characters, and also, suppress the receiver from accumulating echoed characters while it is sending.

If your converter is an NI-serial (USB-485/x) series, know that there is control of the wire mode, programmatically available via a VISA property node.  This property ONLY works for NI's own converters - it'll throw an "unsuppported" error if you try to invoke it on a non-NI device.  Also note, it is not part of the "VISA Configure Serial Port" VI you're using.

What manufacturer of USB to RS-485 converter are you using?

Dave

[vishalshinde885@gmail.com]

thanks david.....

as you suggested i made some changes like

Tx+ to Rx+, and its Tx- to Rx-, then wire the resultant pair to the meter.

Bt still i am having same error..

i can't tell the exact manufacturer of converter bt here is the pdf file i got with it...

[DavidBoyd]

Well, that converter is definitely using a Prolific chip.  Unfortunately, I don't have one of those on hand so I can't really load up the driver for it to check.  But if you go into the Windows Device Manager and select this device's properties, do they include an advanced properties page where you can set the RS-485 wire mode?  Should be "2-wire", "TxReady", "TxAuto", something like that, to describe the tranceiver control.  Where did you get those Windows drivers?  From the converter vendor?

To reiterate - this is only a guess as to what might be amiss with your setup.  I'm assuming you've already ensured the obvious - that the meter is set for 9600 baud (as was your sample code); "even" parity is the standard setting for ModBus/RTU, but other settings are allowed so the meter may be set differently.

But wiring and transmitter control are likely suspects in a new RS-485 setup.

Dave

[vishalshinde885@gmail.com]

yes i have installed profilic drivers which i god from vendor in cd....
there is advanced setting bt it not allowed to change...
all parameter of energy meter are clear and set correctly......
pls suggest something that my setup will run properly....thank you

[DavidBoyd]

What are you not allowed to change? Prolific's port driver settings? Are you logged in with an non-privileged account under Windows?

Other than what I've posted already, I don't know what else to suggest. I don't use that particular NI Modbus library (I have my own).