How to read ASCII from PLC memory location

[ctipete]

How can I read ASCII data stored in a PLC memory location from LookOut?

[Khalid]

Well, it depends. Usually, the memory location in the PLC will have an address. And there's a communication protocol for "talking" to the PLC. Using the address and the communication protocol we can get the data, using the ASCII Object for instance.

What PLC is this? Does Lookout have a driver for this? If the driver exists, then we may not need to use the ASCII Object; one of the datamembers should get us this data.

Regards,

Khalid

[ctipete]

Thanks for the help Khalid.

I should have given more detail in my post. I can connect to the PLC fine (it's a DierectLogic 205 series with a 260 CPU). My connection is Ethernet. I have no problem reading and writing to Vmemory locations or to input and outputs of the PLC. In this application I'm saving ASCII data from a Keyence barcode reader directly into Vmemory locations of the PLC through the serial port of the PLC. What I need to do now is view that data (in ASCII) in Lookout. When I view the addresses (i.e. DL1.V2000) with ASCII data stored in them through Lookout all I "see" is the decimal equivalent to the ASCII. Is there anyway to convert this back to ASCII? I know Lookout has a ASCII com driver that I could use if I could physically connect
the barcode scanner to the PC however this would not be possible, the barcode scanner has to be connected to the PLC on the production floor. Lookout is great, I�ve been using it for years but I really wish it would let you designate the type of data it�s reading (BCD, HEX, OCTAL, Decimal, TEXT, etc.), rather than always assuming it�s decimal.

If you need any other info please ask�

[Khalid]

Hi.. Sorry for misunderstanding your question.

Well, this is a tough one. As you mention, Lookout doesn't provide an easy way to convert to ASCII.

I see two crude ways of doing this:
1. Write an "ASCII look-up utility" inside your process (may be using DataTable??)
2. Use the Serial port and the ASCII Object. No, this approach does not connect to your scanner; instead it just spits out the data and reads it right back in using just the serial port. HERE is an example showing this. Note that this will consume your IO points.

Will let you decide which approach is more crude 🙂

Regards,


Khalid