Roche Cobas C111 - Checksum Calculation; Message Frame; The Intermediate Frame; The End Frame

cobas c 111
Host Interface Manual
Version
2
.1
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7.1.5 Checksum Calculation/ Message Frame
7.1.5.1.1 The Intermediate Frame
[STX] FN
T
ext first char. ......
T
ext last char. ETB CH CL [CR] [LF]
7.1.5.1.2 The End Frame
[STX] FN
T
ext first char. ......
T
ext last char. ETX CH CL [CR] [LF]
[STX]
The ASCII code 2, indicating the beginning of a frame transmission.
FN
The frame number modulus 8. Frames of a single Transmission Phase are
consecutively numbered beginning with 1. So FN runs from 1 to 7, continues with
0, 1, and so on. Use ASCII codes for the digits ‘0’ to ‘7’ (48-55).
Text
The data content of a frame (max. 240 characters).
Records are sub-divided into intermediate frames with 240 characters.
Maximum is indicated by [ETB]. The only or last remaining frame is indicated by
[ETX]. Different records must be sent in different frames.
[ETB]
The ASCII code 23 (17hex), indicating the end of the text block of an inter-
mediate frame.
[ETX]
The ASCII code 3, indicating the end of the text block of an end frame.
CH, CL
Represents the high nibble (= most significant 4 bit) respectively, the low nibble
(=least significant 4 bit) of the 8-bit checksum. CH and CL are represented as
two digits of hex numbers. The checksum is the modulus 8 of the sum of ASCII
values of the frame characters starting with and including ‘FN’ and completing
with [ETX] respectively [ETB].