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BK Precision 4070A User Manual Rev.2.2
53
7.7.2 Using your own program
You may use your own application program to send the arbitrary waveform data to the 4070A.
To download a waveform to the 4070A, you need to send the following to the 4070A through the serial port:
1. A two character header consisting of
a) The “W” character. This tells the 4070A to expect the download of an arbitrary waveform.
b) A single character, which specifies the data format. The character may be
“F” for floating point or decimal format
“T” for time & value floating point format
“D” for digital format
“H” for hexadecimal format
“I” for Integer format
“B” for binary format
2. The waveform data values
3. An optional “X” or “x” character at the end of the data. The “X” character denotes the end of data. If the
“X” character is missing, the 4070A will assume all data has been sent after 1 second timeout.
White space (spaces, carriage returns, tabs, etc.) is allowed before or after the W character. Whitespace may come
after the format character except for Binary format. (For more information on data formats, please refer to section
9.0)
EXAMPLE: Sending the following characters downloads a four point waveform in floating point format:
W F .1234 .6874 -2.345e-1 -1.0
The serial port on the 4070A defaults to the following parameters: 1 start bit, 8 data bits, 1 stop bit, no parity. It is
important that the sending program’s baud rate match that of the 4070A. To inspect or change the 4070A’s baud
rate, press the Mode key and then the Offset key. For more information changing the baud rate, please refer to
section 5.20.
You do not need to tell the 4070A how many points are in the waveform, or which point is the last. If the 4070A
does not receive any characters over the serial port for a 1 second time-out, then the 4070A assumes that all arbitrary
waveform points have been received. If the 4070A is in Arbitrary Waveform mode, the new waveform will be
generated immediately after the time-out.
The 1 second time-out can be avoided by placing an ASCII “X” character (upper or lower case) at the end of your
data. This character tells the 4070A that the end of the data has been reached. The 4070A will then begin generation
of the new waveform immediately. The “X” character cannot be used with the Binary format.
Make sure that there are no interruptions exceeding 1 second while downloading a waveform, else the 4070A will
time out and end the download. Also, if you do not have an “X” character at the end of your data then you must stop
sending characters to the 4070A for a minimum of 1 second so that the waveform will be generated.
An example program ARB.BAS is included on the supplied compact disk, which demonstrates downloading
waveforms in a variety of formats directly from the program to the 4070A.