HART or Modbus protocol

[jack1]

Hi Bob

Thanks for info and sorry for delay in reply, but been working away all last week.

I have just had another CMF010 arrive, but with core processor this time for the next project and have ordered the ProLink software, as this unit will need all of its calibration values entering for fluid being measured. I have had a look at the manual for the RTF transmitter and can see what you mean regarding the reset proceedure. However I think that I will try to 'talk' to the New flowmeter using the RS485 connection first with Modbus on Labview Vi's (and the Prolink software when it arrives) and see how I go before tackling the RFT transmitter again. If I still have no joy then I will contact Albert as you suggest, but wanted to 'have another go' before admitting defeat!

Thanks again

Jack

[osopicaso]

hello everybody, i have a problem with micromotion 9739, i need configure the network id 16 and in hart protocol only can configure to 15, you know any program modbus to can the address 40312 to configure the id 16. I try with a program in DOs called MB, but i cant comunicate with the unit.We knows other software. With PACTware 3.0 is possible configure the id of this transmitter.
Thanks

[sbuckingham1011]

Hi all,

I know this thread is rather outdated but it relates exactly to what I'm having struggles with.  I have MM's RFT9739 set up and communicating properly using the 5 CH MVD READ vi that I found on another thread.  The only question I have is how to find the register for density.  From the Modbus mapping PDF from MM, it seems that the density register should be 249 and 250, but when I try it, I end up with a steady value of 0.3 g/cm^3, which is not what I would expect from liquid CO2 at room temperature.  If anyone knows what registers I should be calling in order to record density, please let me know.

Thanks,

Steve

[Bobad]

Steve,

When you state a 'steady value of 0.3g/cc'. the floating point number should be giving you 7 significant digits of which the last 3 will always be random noise. Is that what you are seeing?

Try reading temperature at 251/252. That should be very obvious if it is correct.

Bob A.

[sbuckingham1011]

Bob,

The temperature reads out at 22.56 degC, as it should.  Also, the other variables (mass flow, volume flow, total mass, and total volume) read out correctly as well.  It's just the density that holds constant at 0.3, and there seems to be no noise in the reading like the other variables have.

Steve

[Bobad]

Osopicaso,

The HART address is at address 40047. HART is always limited to 0-15. You can't go higher with a numbered address. However, you can give tag names to each transmitter. Then use HART command 11 to get the Unique ID number. Then you can address the tag names instead of the short address number.

MODBUS address is at 40313. MODBUS can have addresses from 1-247. However, RS485 limits are usually limited to 32 devices.

Bob A.

[Bobad]

Steve,

Can I ask you what the exact MODBUS command you are using to reference the density? Decimal or Hexidecimal format is fine. The Micro Motion response would be even better.

Bob A.

[jack1]

Steve

I had similar problem when trying to read some of the registers of the CMF010 sensor that started this thread a while back (and others since).

Found that when looking at the sensor using Micro-Motion Prolink the values that were read from registers were fine but still no luck with Modbus routines in Labview. In the end it turned out that one of the problems was the cutoff values for those registers had been factory set to turn off below a certain value, hence no value or a stable value that was meaningless. Modifing the lower limit cutoff solved the problem but involved using Prolink. Unsure if this is applicable to your problem but thought it might be worth a mention,

Regards  Jack

[Ryan Cattley]

Was a solution found that allowed communication via labview only?

I am in the process of setting up labview to be able to do network datalogging from a rft9739 transmitter/flow meter. Do any of you guys possibly have a VI that does some very basic functions like temperature control and mass flow data that I can use as a base/starting point and add on to?

Thanks,

Ryan

[jack1]

Ryan

I have attached a vi that I cobbled together a while back from info on this forum. It was used to develop code on an Emmerson CMF010 Corioliss flowmeter using RS422 link.

It might help you as a starting point,

Jack