Sensoray 626 - Manual (Page 28)

Sensoray Model 626 Instruction Manual 26
13. Analog Inputs
There are 16 analog input channels (0-15). Each channel can be set to have a ±5V or ±10V range, which
will return a 16 bit value (including the sign) in the range ±32767.
A ‘Poll List’ is used to setup the A/D converter. This is a list containing 1-16 commands that will be
executed sequentially every time the ReadADC command is used. Each command tells the converter
which channel to convert (0-15) and what range to use (
±5V or ±10V). The converter starts with the first
command in the list and continues until it reaches a command with a ‘1’ in bit 15 of the command or
until the 16
th command is executed. The results are placed in the array Data[0..15]. If the same set of
channel & range combinations need to be read again the user needs only to execute another ReadADC
command and the old Data will be overwritten with the new. When a new poll list needs to be set up, the
CloseADC command needs to be executed to close the old list and then the ResetADC needs to be
executed with the details of the new poll list. This poll list approach makes reading several channels
much faster. Conversion takes approximately 20usec/channel. Once completely finished with the ADC
the CloseADC command should be executed.
14. Analog Outputs
The analog channels have a 14 bit resolution (including sign).
It takes approximately 200
µS to convert the digital value to an analog output voltage.
To use the Digital to Analog converter call the WriteDAC function and supply a channel and an output
value between –8191 and +8191. This will be converted to an analog voltage between
±10V at the
specified output channel.
Each D/A has a sense input that should be connected to the D/A output at the end of the wire used to
connect to whatever external circuit is used with the D/A. This will help keep noise down.
If this feature is not used then insert the jumpers which in effect connects the sense input to the D/A
output right on the board.
J6, J7, J8 & J9 are inserted to disable the sense inputs for channels 0 -3 respectively.