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ALYA VT200 communication protocol

Supported device types and versions
Communication line configuration
Communication station configuration
I/O tag configuration
Literature
Changes and modifications
Document revisions

Supported device types and versions


This protocol enables to read the weighted values from the scale VT200 produced by ALYA Poprad. In addition to reading net weight and tare, it enables reading signs from keyboard, EAN-code and controlling the built-in monochromatic LCD display with a resolution 240x64 pixels.

Communication line configuration


  • Category of communication line: TCP/IP-UDP
  • Parameters of UDP line:
    • Host: IP address of scale configured in the parameters of scale
    • Port: UDP port of scale where requests are send. Default value (according to the documentation) is 3396.
    Note: The parameters of backup server (Host and Port) are not used in this protocol.

Communication station configuration


  • Communication protocol: ALYA VT200.
  • Address of station is irrelevant and need not be defined. Only one station may be configured on one line.

Station protocol parameters

Key word Full name Meaning Unit Default value
LP Local Port UDP port where KOM awaits responses from the scale. Permitted values are in range 1-65535. - 3396
DT Data Timeout Timeout receiving message from scale on call from KOM process. sec.mss 0.500
ND No Delete Setting value to True will cause KOM process not to send buffer delete requests during reading of keystrokes and barcodes. Parameter is useful only during tuning of communication. - False

I/O tag configuration


I/O tag address I/O tag type Meaning
NETTO Ai Net weight in kg.
Note: If a scale reports the unsteady status (see I/O tag STEADY), I/O tag will be Invalid.
TARA Ai Tare in kg.
Note: If a scale reports the unsteady status (see I/O tag STEADY), I/O tag will be Invalid.
STEADY Di Information whether a scale is steady (True) or not yet (False).
ZERO Di Information whether a scale shows null weight (True) or not (False).
RANGE Ci Scale range: 0, 1 or 2 according to the standard EN 45510
KEYCODE TxtI Keystroke(s) read from keyboard.
Note: After reading keystroke(s) from a keyboard, they are deleted from a keyboard buffer so that during next reading from scale, this I/O tag is set to Invalid (unless parameter ND is set). Therefore, it is necessary to handle keystrokes within ESL script.
BARCODE TxtI EAN-code read from a bar-code reader.
Note: After reading bar-code from a bar-code reader, it is deleted from the reader so that during next reading from scale, this I/O tag is set to Invalid (unless parameter ND is set). Therefore, it is necessary to handle bar-codes within ESL script.
DISPLAY TxtO I/O tag that is used for communication with monochromatic display on scale. The string must consist of binary data in the format which is stated in the manual from a producer.
Message format is <XH>&ltXL>&ltYH>&ltYL>&ltWH>&ltWL>&ltHH>&ltHL>&ltdata>, where:
  • XH - high byte for X axis (binary)
  • XL - low byte for X axis (binary)
  • YH - high byte for Y axis (binary)
  • YL - low byte for Y axis (binary)
  • WH -high byte for width of bitmap (binary)
  • WL - low byte for width of bitmap (binary)
  • HH - high byte for height of bitmap (binary)
  • HL - low byte for height of bitmap (binary)
  • data - binary data of bitmap
Notes:
  • X axis and bitmap width must be divisible by 8.
  • Axes of upper left corner of display are X=0, Y=0. Axes of lower right corner of display are X=239, Y=63.
  • One byte of data describes group of eight pixels in one line of display. So, from the axis (0,0) to (7,0) there is necessary one byte, the highest bit of which is described by a pixel (0,0) and the lowest bit by a pixel  (7,0).
  • All display can be described by (240/8) * 64 = 1920 bytes. But, maximum length of UDP packet is 1500 bytes, i.e. if whole display must be redrawn, it is necessary to send more queries (e.g. first half of display and second half of display).

Literature


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Changes and modifications


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Document revisions


  • Ver. 1.0 – July 14, 2015 – created document
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