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eal4LabVIEW - Writing to PLC Global Register

eal4LabVIEW - Writing to PLC Global Register

New Poster

I am trying to write data to Real Time Output (MDT) of the Indra Drive using eal4LabVIEW. I have attached the screenshots of drive configuration in IndraWorks and LabVIEW Code.

I am able to read the data from Real Time Input (AT) using PLC Global Registers G16 and G17 using parameters P-0-1316 and P-0-1317. Bits map correctly to what is displayed on the HMI. 

When writing to the output assembly which is using PLC Global Registers G0 and G1 using Parameters P-0-1370 and P-01371, I don't get any error but there are no bits set on the register when I read it back. 

Is there a special configuration needed to write data to Real Time Output (MDT)?


Long-established Member


MDT and AT containers are used for master communication protocolls like sercos or EtherCAT. Parameters within these containers are written cyclically from master. This is why you can not write via EAL to parameters of these containers.

With EAL you can write directly to parameters like P-0-1370 or P-0-1371.

Therefor you need to remove these parameters from MDT and AT container. You can also try to write a parameter which is not mapped in MDT of your drive like P-0-1372

Writing to other parameter like P-0-1372 does work and I can read back the data. What I am looking to do is write to I/O assembly of the Drive. I tried using Ethernet/IP communication in LabVIEW but I found out that LabVIEW cannot act as a scanner so I was not able to set the bits on the I/O assembly. I am now using eal4LabVIEW and running in to the same issue again. Is there a way to access and set the bits in the I/O assembly. 

I am trying to communiate with a Riveter controller (Henrob by Atlas Copco) which contains this Indra Drive. Please find the attached EDS file. 

Long-established Member

You can not set bits of parameters which are mapped in MDT because the EthernetIP scanner will cyclically overwrite these parameters.

This means you need to ask the EthernetIP scanner to change the bits, or you need to remove the parameter from MDT.