Analog Output

Writes to analog outputs of the Q8 data acquisition system.

Library

qctools

Description

The Analog Output Module for the Q8 series of I/O cards provides a mechanism for setting the voltage levels of any analog output on an installed Q8 I/O card. The block can take a scalar or vector input. The input may either be in units of volts or a raw 12-bit converter values. The analog outputs may also be configured for a 0 to 10V (unipolar, 10V), -5V to +5V (bipolar, 5V) or -10V to +10V (bipolar, 10V) range.

Parameters and Dialog Box

Board Number

The board number of the I/O card. If there is only one Q8 board in your system, then the board number should be zero. The second Q8 board in your system is board number 1, etc.

Channel(s) to Use

The channel numbers corresponding to each input. For example, if there are 3 inputs, then the entry [3,2,0] assigns input 1 to D/A output 3, input 2 to D/A output 2 and input 3 to D/A output 0. The channel numbers may range from 0 to 7, since there are 8 D/A channels on the Q8 I/O boards. The selected channels are all updated simultaneously.

Mode(s)

Mode for each output channel specified in the Channel(s) to Use parameter. If Channel(s) to Use is [3,2,0] as above, then an entry of [0,1,0] for the Mode(s) will put D/A channels 3 and 0 in bipolar mode, and D/A channel 2 in unipolar mode. A scalar value applies to all channels.

Range(s)

Range for each output channel specified in the Channel(s) to Use parameter. If Channel(s) to Use is [3,2,0] as above, then an entry of [10,5,10] for the Range(s) will put D/A channels 3 and 0 in 10V range, and D/A channel 2 in 5V range. A scalar value applies to all channels. Entries may only be 5 or 10. A value of 5 is invalid for unipolar mode since the 0 to 5V output range is not supported by the hardware.

Initial Output(s)

Initial value for each output channel specified in the Channel(s) to Use parameter. If Channel(s) to Use is [3,2,0] as above, then an entry of [0,2.5,0] for the Initial Output(s) will set D/A channels 3 and 0 to 0V, and D/A channel 2 to 2.5V when the simulation is initiated. A scalar value applies to all channels.

Final Output(s)

Final value for each output channel specified in the Channel(s) to Use parameter. If Channel(s) to Use is [3,2,0] as above, then an entry of [0,2.5,0] for the Final Output(s) will set D/A channels 3 and 0 to 0V, and D/A channel 2 to 2.5V when the simulation is terminated. A scalar value applies to all channels.

Sample Time

A sample time must be specified for all discrete blocks. A value of -1 causes the block to inherit its sample time from its input. A positive value specifies the sample time explicitly. Set the value to simget(bdoot,'FixedStep') to extract the sample time from the RTW Options dialog, under Solver/Fixed step size. A numeric value rather than 'auto' should be specified in this dialog field for this default to make sense.

Input Volts

When this option is checked, the input signal to the block will be treated as Volts. Hence, an input value of 5 will result in 5V being produced at the output.

If the option is not checked, then the input is treated as raw 12-bit D/A converter values. In unipolar mode, a value of 0 corresponds to 0V and a value of 4095 (0x0fff ) corresponds to 9.998V (+10V – 1 LSB). In 5V bipolar mode, a value of 0 corresponds to -5V and a value of 4095 corresponds to +4.998V (+5V – 1 LSB). Similarly, in 10V bipolar mode, a value of 0 corresponds to -10V and a value of 4095 corresponds to an output voltage of +9.995V (+10V – 1 LSB).

Simulation Output

When the Simulation Output box is checked, the block will have an output port. During normal simulation (as opposed to running real-time), the signal at the input will be quantized to the resolution of the D/A and produced at this output. This check box has no effect on the real-time code.