B&K 4070A User Manual
Page 64
BK Precision 4070A User Manual Rev.2.2
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7.8.6 Binary Format
This is the fastest way to send points to the 4070A since it transfers the data point with only 2 characters. (It is also
the least forgiving as far as getting the data sent correctly).
Each data point is a 16-bit word, which is sent to the 4070A in two bytes. The high byte is sent first, followed by
the low byte.
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 4070A, 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 4070A.
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 Binary format:
1. IMMEDIATELY after the “B” character in the header the 4070A expects the first high byte of data point 1. No
white space is allowed after the “B” in Binary mode.
2. The high byte of each data point is sent first, followed by the low byte.
3. 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 binary format with SYNC Out set high point #3. This is the same waveform data that is
given as an example in the Hexadecimal format section.
W B<00><00><40><00><fe><d8><45><70><80><00><ff><f0><e6><d0><00><10><00><f0><0c><06>
where <xx> represents the 8 bit binary value of the data byte sent to the 4070A. Note how white space is NOT
allowed in Binary mode and the binary data begins immediately after the “B” character.
NOTE: In binary format, you cannot use an “X” character to denote the end of data. (Since the ASCII “X” byte
could be interpreted as another binary value).
NOTE: ASCII characters do not represent these data values. A binary disk file cannot be viewed using an ordinary
text editor. (Garbled, non-printable characters will result). You must use a hex editor to view such a file.