Espec RS485 error 0

[Lcz38]

Hello everyone, 

Currently, i work on an oven from Espec, the EHS 221MD for HAST reliability

test and i want to be able to communicate with to collect some data ( temperature, humidity...) and start / stop the tests. 

This oven work with RS485 serial communication.

I got the codes to send to do this from the manufacturer, but each time i start my VI(see attachement) , i have this error : 

I don't really know, why i have this error, maybe a hardware problem from my converter ?  (MAX detects it)   

As converter, i use a MOXA Uport 1100, i use it on RS485 4wire and I have perform this as wiring : 

Can someone help me with this.

Thanks in advance for your answer.  

Regards,

Lucas 

[Deus_ex_Machina]

Hi there,

In the error message, it is mentioned that probably the NI-488.2 driver is not installed.

You can check if it is installed by going to NI Package manager on your PC and search for it under the [Installed] section.

I recommend you to check the availability first, to move forward with troubleshooting! 🙂

[Albert.Geven]

Hi

Error 0 is normally used to indicate no error and you really don't need the NI_488 driver because you don't need this for rs485.

[Albert.Geven]

The basic mistake you have in your vi is that you don't allow a bit of time for the espec to respond.

I cleaned up your code to make it better readable and added a delay before reading the number of bytes.

A better alternative, you know the end character is to use the stop at end character.

Just fill in 255 for number of bytes to read or more if you expect more data.

I also added a case statement that in the true case uses the end character and in the false the delay.