16AO16:Wave

The General Standard 16AO16 is a 16 bit analog output board. Up to 16 channels are supported on the board. See 16AO16 for details. In the 16AO16:Wave configuration, it is used as an arbitrary wave form generator.

Reference Information 16AO12

I/O Card Model Number

CS-GS-16AO12x.

I/O Driver Model Number

WCS-GS-16AO12.

I/O Module License:

ICS-SWB-1214.

Reference Information 16AO16

I/O Card Model Number

CS-GS-16AO16x.

I/O Driver Model Number

WCS-GS-16AO16.

I/O Module License:

ICS-SWB-1214.

Left Hand Side

Sampling Rate (Hz)

Rate at which the board outputs its sample. The maximum rate the board supports is 449.5 KHz.

External Clock

Specifies the use of an external clock instead of the internal clock. This is usually used when multiple 16AO16:Wave boards are defined with one board providing the clocking for the other boards. This ensures that there is no drift between the various boards so they will all be perfectly in phase.

External Sync

Specifies beginning output of the wave form when the board receives a low to high to low transition on its external sync pin. This is used to keep multiple boards perfectly in sync by starting all their output at the same time.

Voltage Range

Selects the voltage range for all the channels on the board. The raw value is a 16-bit value whose range should can be mapped to volts using engineering unit conversions.

Filter

Selects the pass-band elliptical filter present on some 16AO16 boards used at initialization. The filter can also be changed at run-time via the SimWB API. The filter are common to all channels on the board.

A

55 KHz

B

145.6 KHz

Consult the General Standards web site for more information.

Channel Column

Channel Number.

Frequency (Hz) Column

Frequency at which the wave form file will be repeated on the channel.

Wave From File Column

Wave form file mapped to the channel.

API Functions

int ccurAsyncIO_ao16SetFrequencyWave(int boardNum,
int channelMask, double frequency, char *waveFile)
int ccurAsyncIO_ao16Pause(int boardNum)
int ccurAsyncIO_ao16Resume(int boardNum)
int ccurAsyncIO_ao16Start(int boardNum)
int ccurAsyncIO_ao16Stop(int boardNum)
int ccurAsyncIO_ao16SetFilter(int boardNum, int filter)

Right Hand Side

16AO16:Wave is one of the few boards to have an alternate form on the right hand side of the I/O Mappings dialog.

Mapping Tab

Instead of mapping channels to I/O points, wave files are mapped to each channel. The real-time host will interpolate the data points specified in the file via a DDS algorithm so that when the number of data points specified in the file does not match the number needed for the sampling rate, the correct wave form is still output.

Wave forms are mapped to the selected channel in the same way that I/O points would be on other boards. Select a channel by clicking on it, then click on the check box next to the wave file you want to map to that channel.

Delete

Deletes the selected wave file or folder.

Create Folder

Creates a new folder with the name specified in the adjacent text box in the folder selected in the Wave Form File List. If no folder is selected, the new folder will be in the root of the list. If a wave file is selected, the new folder will be in the folder containing the selected wave file.

Upload Tab

Uploads wave files to the real-time host.

Destination

Shows the destination folder on the real-time host.

Link

Creates a symbolic link to the selected file on the real-time host. The Control Center must be running on Linux and the real-time host must have the source file system mounted in the same directory as it is on the client system.

Upload

Uploads the selected file to the destination folder on the real-time host.

Help Tab

Provides brief help on mapping for 16AO16:Wave devices.

Wave Form Files

Wave form files are in ASCII and are a list of voltage or raw values between the maximum and minimum voltage range specified. An example file specified using floating-point voltage values is:

FORMAT_FLOAT

-10.000000 -9.998779 -9.997559 -9.996338

-9.995117 -9.993896 -9.992676

-9.980469

An example file using unsigned 16-bit integer hex numbers to specify raw values is:

FORMAT_HEX

0000 0004 0008 000c 0010 0014 0018 001c

0020 0024 0028 002c 0030 0034 0038 003c

0040 0044 0

Asynchronous I/O Task: ao16wavefasync

This process runs asynchronous to the test cycle and handles outputs to the GS 16AO16 board when the board is configured in the RTDB as a wave form board. The board has a maximum of 16 output channels. This process is multithreaded.

There is one main thread that processes commands from the command FIFO queue.

There are two additional threads that share the workload of output the wave forms continuously to the devices.

Contrary to most other hardware devices supported by SimWB, there is no mapping between RTDB variables and hardware channels on the board.