Scu21 & Txdu Instruction

[frank.raymond 0]

Hello, Been struggling trying to use the TXDU Instruction & a SCU21 card. I'm using a NO A202.02 for port 2. I've set the serial unit using the CX programmer (no protocol). No errors. Have the run and rdy leds however I never see data the SD leds. Trying to send info to hyperterminal. Not sure if I need to write info in CIO and D registers for further setup etc. Thanks

[Jay Anthony 118]

Please tell us how the instruction operands are set and what are the values for each operand.. Ex. TXDU D1000 D2000 D3000 D1000 - #4142 D2000 = #0000 D2001 = #0010 D3000 = #001A

[frank.raymond 0]

Thanks for the response: TXDU D18500 #0 D18509 For grins and giggles I copied the program from another PLC along with the memory files. The difference is I added an ethernet card. The SCU is unit #14 and the eth unit is #15. I first downloaded the PLC portion and got errors for both the serial and ethernet boards, I went into program mode and created the IO. AFterwards I configured the ethernet card and sent the config back to the card. I then configured the SCU and sent it's data back to the unit. Restarted the program. Also cycled power. I no longer have an error on the SCU however I do have an ECH??? error on the ethernet card (I don't this is causing my problem but could be wrong). I am also using the CPU serial port writing and scanning a barcode reader. Pretty straight up stuff. From the RCV register I am using an XFER command to put the data into a register for sending out port 2. I configured port 2 to use a '# sign" for the message preamble. Still can't see any LED activity on the SCU nor when I hook up to hyperterminal !#@!%^&

[Jay Anthony 118]

Cannot use #0 for the control word because the instruction requires C and C+1. TXDU D18500 D1000 D18509 D1000 = #0000 D1001 = #0110 for Unit #0 (0 +hex10), port 1, communication buffer #0

[frank.raymond 0]

My blunder!!! TXDU D18500 D650 &12 D650 = 0000 D651 = 2081

[frank.raymond 0]

Problem has been resolved. My unit address was set at E and the PLC I copied from is set to 0. However when I read the attachement it says to set destination unit address to 80h + 4 * unit number. This would make the destination unit address 84h or 0 (multiply by 0)???? What am I missing??? As I said it does work now. Thanks to all. This is my PLC forum of choice. frank in Alabama

[Jay Anthony 118]

The formula for port 1 is 80Hex + (4 x Unit number). The formula for port 2 is 81Hex + (4 x Unit Number). Based on the above formula you have the TXDU directed to SCU Unit #0, port 2.

[frank.raymond 0]

I think I need to reveiw the rules of math and get better glasses. Thanks a bunch!!!