Modbus driver

[rogue]

Hello there,

I'm trying to use a  MODBUS RTU driver (serial communication driver) for
Labview. but i don't undersatnd what is ''decimal point '', ''process values'' ''digital read''

please someone  can  explain to me who it's work??

[Khalid]

Rogue,

It appears that these VIs were written specifically for a particular device.  As you may know already, Modbus protocol itself doesn't support floating point numbers.  However, there are ways to workaround this.  Typically, two adjacent registers are together used to build one floating point number using the IEEE floating point notation. 

However, in these VIs, it appears that the device they were written for can be set to display so-many decimal numbers.  And you just write an integer and it adds the decimal point at the right place.  And vice-versa, i.e., you read integer values but place the decimal point yourself in the values read (weird way of doing this, IMHO).  In any case, this is why, it appears, you have the "Decimal points" array on the front-panel.  And "Setpoints" are the values you want to write to the device. 

IMHO, this does not seem like a very generic Modbus driver.  You may want to try NI's Modbus library instead (which itself can be improved further):

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71

Regards,

-Khalid

[rogue]

Dear Khalid

thank you very much for you reply, but I have a have a problem, the NImodbus library doesn't work with Labview 7.0, and I don't have a Labview 7.1, do you know if this library exsist on  version7.0?

[unclebump]

Look here.

http://forums.ni.com/ni/board/message?board.id=170&message.id=135288&requireLogin=False