Serial Communication Protocols - Pavone Systems MCT 1302 Technical Manual

Touch screen batching version with rs232 serial, analog and fieldbus

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Table Of Contents

Table of Contents

CONTINUOUS ASCII PROTOCOL

The continuous sending is performed at the weight update frequency, compatibly with the serial

transmission baud rate. In case of communication on the Ethernet port, the frequency of the continuous

transmission is limited to 12.5 Hz.

STX

where:

STX (start of text) = 0x02h

ETX (end of text) = 0x03h

EOT (end of transmission) = 0x04.

<status> = character coded as in the following table (bit = 1 if condition is TRUE):

Bit 7

Bit 6

<weight> = field consisting of 8 ASCII characters with the weight value justified on the right without

non-significant zeros, with any decimal point and negative sign.

The sent weight value can be the net weight, the gross weight or the peak value, based on the selec-

tion of the sent data (MODE parameter) in the setup menu of the serial communication ports (see the

relevant paragraph).

In overweight conditions, the field assumes the value: "^^^^^^^^".

In conditions of weight greater than 99999, the field assumes the value: "_ _ _ _ _ _ _ _".

In conditions of wrong reading, the field assumes the value: " O-L ".

<cheksum> = sum of control of string data. It is calculated by executing the exclusive OR (XOR) of all the

characters from STX (or from <Addr>) to ETX excluding the latter; the result of the XOR is decomposed

into 2 characters considering separately the 4 upper bits (first character) and the lower 4 bits (second

character); the 2 characters obtained are then ASCII coded;

(example: XOR = 5Dh; <csum> = "5Dh", namely 35h and 44h).

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