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Hondaman's Achievements


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  1. I have need of an HMI-PLC unit with a serial (RS-232) port and possibly a USB port (for exporting collected data records) that can communicate as follows: 115Kb data rate, * bits, Odd parity, 1 stop bit, <STX> start, <ETX> end, followed by <bcc> checksum code at tail end which consists of an XOR 8-bit value of all characters preceding it (including the <STX> and <ETX> characters. I realize I can create the string within the ladder code prior to TX, but the protocol itself, adding the <bcc> at the end, is sometimes problematic with HMIs, as not many of them support this functionality. I have used the Unitronics with the built-on HMI screen before, reading fast barcode scanners, worked well. But, that was a canned protocol, no check code, no variable-length strings, etc., so ths one is tougher. Any recommendations?
  2. You guys sure know these little PLCs! I need some advice, and maybe a ''thumbs-up" or "thumbs-down" advice: I am working with some [very] fast-communicating sensors that use 115kb RS-232 in the following format: <STX>[put ASCII here, in various lengths]<ETX><bcc> where the <bcc> is the checksum as an XOR of each character prior to the <ETX> itself. The [fixed] protocol is running at 115kb, e,8,1. I must both compose and TX such strings and read such strings from these devices, putting their fast-moving output on a screen. I am having some difficulty in finding an HMI or maybe PLC-HMI that I can use to COMM back and forth with the sensor: I have used some of the Unitronics (U90 and [something]700 w/screen) before, but don't know if they will let me do this: can you advise? Thanks, and Merry Christmas (2016).
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