Fairford

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Posts posted by Fairford

  1. Hi

    I am a DaqFactory novice so please excuse my ignorance if the following is trivial

    I’m connected with a Sprint DC Variable Speed Drive through the RS232 port. Communication is established and I can perform basic parameter functions.

    Using the line below, I can set the speed to 100%

    device.Sprint.Write(chra({0x04,0x30,0x30,0x30,0x30,0x02,0x41,0x61,0x31,0x30,0x30,0x03,0x12}))
                                           (EOX) (GroupID)(   Unit ID  )(STX)( Mnemon)(      Value         )(ETX)(BCC)
    Where:
    EOX = End of transmission. Clears the line at start of new message
    STX = Start of Text
    ETX = End of text
    BCC = Block Check Character – verification check digit which is exclusive OR of Mnemon to ETX
    Mnemon = Two hex character ASCII mnemonic for parameter. Aa in this case = Speed
    Value = ASCII hex representation of parameter value. In this case 100

    Whilst EOX, GroupID, Unit ID, STX and mnemonic can remain fixed in each transmission, I’d like to be able to dynamically change the value and check block (BCC) so that I can change the speed of the drive by reading a slider value (or similar).

    I’ve tried for many hours to place variables into the chra array to dynamically change the values and BCC, but I’ve failed miserably!

    Please can anyone help.

    With thanks