BNC 630 - Manual (Page 69)

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7.8.5 Hexadecimal Format
This format sends the same two's complement data that Binary format uses, except that each nibble (4 bits) of the hex value is
represented by an ASCII character.
Each data point is a 16 bit value which is sent to the 630 as 4 ASCII characters.
Each ASCII character represents 4 bits as follows:
0000 to 1001 - Represented by an ASCII "0" to "9"
1010 - Represented by an ASCII "a" or "A"
1011 - Represented by an ASCII "b" or "B"
1100 - Represented by an ASCII "c" or "C"
1101 - Represented by an ASCII "d" or "D"
1110 - Represented by an ASCII "e" or "E"
1111 - Represented by an ASCII "f" or "F"
For example, the 16 bit value 1101 0011 0101 1111 is sent as "d35f"
The 16 bit value is in "two's complement" format, which represents a number from -1.0 to +1.0 as follows:
8000 ---- E000 ---- FFFF,0 ---- 4000 ---- 7FFF
-1.0 -.5 0.0 +.5 +1.0
Although a 16 bit value is sent to the 630, the Arbitrary Waveform system uses a 12 bit D/A converter, so not all 16 bits are used.
Only the uppermost 12 bits are used to form the arbitrary waveform point. The fourth lowest bit (bit 3) is sent directly to the SYNC
Out connector on the front of the 630.
Example: The data value E468 is handled as follows:
1 1 1 0
E
0 1 0 0 0 1 1 0 1 0 0 0
4 6 8
These 12 bits are sent to the DAC
This bit is sent to the SYNC Out Connector
Rules for Hexadecimal format:
1. Each Hexadecimal value may have 1 to 4 characters. Negative values require 4 characters since the most significant bit of the
value (bit 15) must be a 1 for negative values. If there are fewer than 4 characters the value is interpreted as positive. Characters
are not case sensitive.
2. To separate each number, you may use commas, tabs, spaces, carriage returns and/or linefeeds, semicolons, colons or basically any
character that is not among the following: 0 1 2 3 4 5 6 7 8 9 a A b B c C d D e E f F X
3. The most significant nibble character is the first that is sent to the 630. For example, to send the value 1234, the 1 is sent first,
then the 2, etc.
4. The SYNC Out output is controlled by bit #3 in the low byte. If this bit is set to 1, SYNC Out is set high. If this bit is set to
0, SYNC Out is set low.
Example
A 10 point waveform in hexadecimal format with SYNC Out set high on point #3:
0, 4000, fed8 4570 8000 fff0 E6D0, 10 F0,C06 x
The “x” character denotes the end of the data and is optional. If the “x” character is missing, the 630 will assume all data has been
sent after 1 second timeout.