Connecting Labview to RS485

[RavensFan]

You should attach your VI.

It is amazing what kind of errors we can find in code when it is possible to see the code!

[Imy7]

Hi RavensFan,

Can you please tell me how can I get the slave address ( from 0 to 247) ?

[RavensFan]

It is probably not 0, because that is an address used pretty rarely when communicating a broadcast message to all devices on the RS-485 bus.

You need to read the manual for your device to see how the address is set.

[RTSLVU]

---

@Imy7 wrote:

Hi RavensFan,

Can you please tell me how can I get the slave address ( from 0 to 247) ?

---

The manual for your device will give you instruction on how to set the address of the device.

The manual should also contain a register map telling you what resister (or registers) to read to get the measurement(s) you desire and how to decode or scale that value to get the actual measurement. 

For instance I have a device where certain measurements are held in two sequential registers. I have to read the two registers, Byte merge the two 16bit signed integers, then convert that to a Single Precision Float, and multiply that times a scaling factor to get the actual value.

[Imy7]

Hello,

Thank yall for your answers , latest updates ,am still struggling I read the manual but it does not contains the registers addresses I got the slave address though but still not able to communicate I got the ''Timeout error'' (code:6101) Everytime I run my VI , I tried many diagrams but didn't work at all I get no response from my  temperature regulator am losing it here so please any suggestions of diagrams that could help me to read the holding registers .

Thank you for your time 

[AaronTeitlebaum]

Once again, you have to post your code (not a screenshot, the actual .vi files) before anyone can give you meaningful feedback.

[RavensFan]

Perhaps there is another, more advanced document, that lists the registers.  You might have to contact the manufacturer.

The modbus protocol might as well not even exist if the manufacturer isn't capable of providing the critical information needed to use their product!

[AaronTeitlebaum]

It looks like the document 8MA10081_EW48_Modbus_EN_0410.pdf which Imy7 tried to link to earlier does list all the available Modbus addresses.

[Imy7]

Hi everyone,

I want to share with you the recent results , so I downloaded the commix 1.4 software to communicate directly with my device via RS-485 USB , the modbus is integrated in my device (temperature regulator Eliwell 4822)
I sent all what it takes but I still get no response I'll share with you three pictures the first one is when I sent the command and the second one it seems like whenever the relay in my device goes on and off I get something but not what I need , and the third one is my device. 

[RTSLVU]

I applaud your efforts to get your device running using another software but honestly this has gone outside the realm of a LabVIEW support forum.

My first experience with Modbus I used the manufacturers software to get my hardware working properly before I started programming.