USTER HVI SPECTRUM, Instruction Manual, Page: 194 / 230

USTER
® HVI SPECTRUM
Instruction Manual
Uster Technologies, Inc. Chapter 14
Appendix • Page 14-8
2.7 Transmission Architecture
This document describes the transmission format of the
HVI SPECTRUM
.
The instrument will transmit records of data from the serial port and can
be configured to transmit particular records. The configuration must
occur prior to the sample testing. All records will be transmitted after all
observations of a sample are finished. Transmission records are
characterized by the following:
•
All records start with a standard header (discussed in Universal
Record Format), followed by record specific data fields.
•
The record length is variable.
•
The data is transmitted as ASCII characters. In other words, the
number 12.5 will be transmitted as four characters, namely “1”
(0x31), “2” (0x32), “.” (0x2e), and “5” (0x35).
•
Records will be delimited by CR (0x0d).
•
Fields will be delimited by “@” (0x40).
•
A checksum is included with all records as the last field.
The checksum for a string is produced by taking the “exclusive-or”
of all characters in the string up to and including the field delimiter
before the last field where the checksum is to be placed in the
record. The checksum will not include the CR delimiting the
records. The checksum value is formatted as a decimal value.
As an example, consider the following HVI Micronaire mean
record:
HVI@MIC@02@100@12:00@01-DEC-93@TEST RUN@1@3.5@n@91@<CR>
Note that <CR> in the above example is a single character,
namely CR (0xd), at the end of this record. The 91 in the last field
is the checksum derived by taking the xor of the 48 characters
before the “91”.