Is the labview DSC module needed for PLC serial connections?

[zerocover]

I would like to connect an Allen Bradley Micrologix 1000 PLC to a PC running labview. I would like to use the PLC for data acquisition and motor control, while using labview for data logging and complex calculations. As such I need the ability to pass single precision integers back and forth between the PLC and labview.

Reading the NI support pages, I found that it might be possible to interface with the PLC via serial connection (RS-232) without the need of further hardware. I would like to know what other software or hardware might be needed. As of now I only have labview 8.6.1. I believe that the DSC module is needed, for an added $649 on top of the cost of labview. Am I right in assuming this, or is there another way to interface with the PLC directly? If I were to use an Ethernet connection would that still need the DSC module?

[Albert.Geven]

You don't need the dsc toolkit. Communication is perfectly possible but the DSC toolkit has already a driver installed with OPC and that makes life easier.

Serial communication or ethernet are both bottom layer protocols that need to be extended to the higher level protocol that makes it possible to exchange data and commands with the allen bradley plc.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000PAbISAW&l=en-US

An excerpt from the NI website shows:

Yes, you can connect to your Allen-Bradley PLC without using OPC servers or the DSC module using the following options:

• Direct serial communication
• Communication over ethernet/IP using LabVIEW

The manual for the former is available on the Allen-Bradley website. The driver for the ethernet/IP is available on the NI Labs page and has instructions included with it.

Related Links:

External link: Allen Bradley Serial Interface API
NI Labs: Ethernet/IP Driver for Communication to Allen-Bradley PLCs

[Robbob]

Albert is completely correct in his statements, but I just wanted to add my two cents.

The DSC module is not required, however when communicating with PLC's, I highly recommend using NI-OPC servers(seperate from DSC module).  NI-OPC servers have a built in driver for the Micrologix devices, and you should be able to set up a connection to the device really fast for you to build tags(channels) and read data.  Of course, paired with the DSC module, you would be able to bring these tags into LabVIEW very easily, but without them you will have to use datasockets, which you simply have to manually enter the channel names in the block diagram to connect to them.  There are built in examples for this as well.

I know your goal was to save a little money by writing the low-level communication yourself, but you would save a lot of time using drivers we have already developed. If you are unsure, download LabVIEW 30 day evaluation and NI-OPC 30 day evaluation, and compare writing the low level driver to using the OPC server.  By the way, I am not a salesman, just giving my engineering experience here 

[Albert.Geven]

Rob

thanks for the update, I forgot about the NI=opc drivers being separately available.