B&K 4070A - Manual (Page 72)

BK Precision 4070A User Manual Rev.2.2
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IF PointVal < 0 THEN PointVal = PointVal + 2: j = 32768!
a = INT(PointVal * j) ' Get a number 0 to 65535
a = INT(a / 16) ' Mask off lower 4 bits ($FFF0)
a = a * 16
IF PointNumber = 2 THEN a = a OR &H8 ' Set SYNC Out bit for second point
a$ = HEX$(a) ' Convert the integer to hexadecimal
' For negative values, the HEX$ fctn will return a 32 bit value, ie $FFFF FFD8,
' so chop off all but the last 4 chars
IF a < 0 THEN a$ = RIGHT$(a$, 4)
PRINT #1, a$ ' Send hex point to 4070A
RETURN
'------------------------- Send Binary data to 4070A ------------------------
' 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.
'
'
' 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 whitespace 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.
'------------------------------------------------------------------------------
SendBinary:
IF PointNumber = 1 THEN PRINT #1, "WB"; ' Put header info before 1st data
' point. Must not have CR or LF after
' Convert the value in PointVal to a two's complement hex number
j = 32767
IF PointVal < 0 THEN PointVal = PointVal + 2: j = 32768!
a = INT(PointVal * j) ' Convert -1.0,+1.0 to 0,65535
a = INT(a / 16) ' Only the uppermost 12 bits are used, so
a = a * 16 ' Mask off the lower 4 bits (AND fff0)
IF PointNumber = 2 THEN a = a OR &H8 ' Set SYNC Out bit for second point
' If you let Basic send a 16 bit variable to a port, it will send the low byte