difference between DeviceStates and DPNRM_DG

Hi,

What are the differences between DeviceStates and DPNRM_DG for DP network?

Hi SariB,

the main difference is the following:

With "DPNRM_DG" you can read the diagnostic data of one DP slave, while "DeviceStates" is used to get status information for an entire IO system (PROFINET IO- or DP master system).

Kind regards
Stefan

Hello SariB,

The DeviceStates function outputs the state of all devices of an IO system. 

On the other hand, DPNRM_DG is used to determine slave-specific diagnostics data.

I attach you the following FAQ in case it helps you in any way regarding the use of the DPNRM_DG function:

With the S7-1200, how do you read out the diagnostics data of a PROFIBUS DP slave with the "DPNRM_DG" instruction and how do you evaluate the data in the user program?

https://support.industry.siemens.com/cs/ww/en/view/17858394

Best regards, 

s7-mencey.

Dear colleaguages,

Thank you for your replies. But I want to know can I use DPNRM_DG instead of DeviceStates? I think, I can and also DPNRM_DG gives me detailed diagnosis datas. Am I right?

Hello SariB,

this depends on your requirements. Of course, you can use DPNRM_DG to get diagnostic data. However, if you use multiple devices, you must call this instruction for each device.

Kind regards
Stefan

Hello Sarib,

Yes, you can use DPNRM_DG instead of Device Status and as you can tell, it will give you a detailed diagnostic of your slaves. However, as Stefan Arcularius correctly stated, DeviceStatus would be a more efficient option as it is not needed to be called for every device.

Best regards,

s7-mencey.