write messages to Bradley SLC-500 PLC

[P.Rayne]

hello...i've come across a hurdle in this...i need to write a couple
of characters from the visulization part of the project to an
ALLEN-BRADLEY SLC-500 PLC. i have been unable/uunsuccesful to find any
VI's or examples for this.

could anyone point me in the right direction or suggest a Forum,
posting etc where i could get some help.

thanks,
cheers...
-U

[AndreOliveira]

Hi,

In order to write this program you will need a driver for your PLC. If you have a driver for this PLC and this driver has OPC Server capabilities you can use datasocket VI's in LabVIEW to read and write from the OPC Server(driver) and consequently to the hardware, make reference to the following address :

http://zone.ni.com/devzone/conceptd.nsf/webmain/DF8C0A4BA2E2B22A86256A3700592BEA?opendocument

Normally the hardware manufacturers provide drivers for the PLC's and they normally have OPC Server capability, since manufacturers want to increases the hardware connectivity.

If you do not have a driver, you may want to consider the National Instruments product called "IA Server with OPC". This is a CD with a set of drivers in it, and all this driver
s have OPC Server capability. The SLC-500 PLC is between the hardware that is supported, however you should pay attention to the following facts:

Use this driver to communicate with the Allen-Bradley SLC5xx line of programmable controllers. This object can communicate with a member of the Allen-Bradley SLC-500 family in the following ways:

· Through a direct DH+ connection using a 1784-KT, 1784-KTx, 1784-PCMK, or 5136-SD card installed in the computer,

· Through the serial port via a KF2 module which converts serial DF1 to DH+,

· Through the serial port using an Allen-Bradley 1747-KE card (which plugs into the SLC chassis and converts DF1 to DH 485),

· Through the serial port using a stand-alone Allen-Bradley 1770-KF3 communication interface module which converts DF1 to DH 485,

· Through a direct DF1 serial connection to a SLC 5/03 or SLC 5/04 programming port, or

· Through a direct DH485 connection using a 1784-PCMK card plus either a 1747-AIC or 1761-NET-AIC mod
ule.


So, make sure you have the hardware required in this list if you want to use the "IA OPC Servers with OPC"


I hope it helps

Best Regards

Andre Oliveira

[P.Rayne]

thank you for the tips Andre, i did try what you suggested.
i progresses thus far... i can now read the data from the PLC. i can
get and diplay messages according to the generated bits on the PLC.
i'm using datasockets to perform the task.

but i'm still confused as to how do i exactly (know) write data to a
PLC. what is it i need to do so as to see that i am actually getting
my data to the PLC?

thanks,

-U

[AndreOliveira]

Hi,

The best way to make sure you are writting successfully to the PLC is finding an output in the PLC that you can monitor, and look at the register that is related to that output.

For example, if you have a LED on the PLC, or even a digital output that you can measure with a multimeter, you would have to find in the PLC documentation what is the register related to this output. Once you have found it, is simply a matter of writing to this register using a Datasocket Write function and verify if the value is really changing the output on the PLC.


I hope it helps

Andre Oliveira

[P.Rayne]

Andre Oliveira :

Thank you much for your help and repeated clarifications. i have the
PLC connected to a monitoring PC and the register could be monitored
thru it presume.

when you say use a DataSocket Write Vi to write to a register, i can
read the data after opening, updating, reading required data and then
writing and then closing the DS. my biggest problem or hurdle is it
all seems so simple, am i doing it right ?

may be if you so choose i could send you what i've done toll date for
yout o take a peek at...

cheers,
-U

[P.Rayne]

I got the problem solved thanks for all the help..!!

cheers,
-u