IO106 Analog input (DMA) / IO106 / Analog / I/O Connectivity / Speedgoat I/O Blockset

Library

Simulink Real-Time - Speedgoat

Description

This driver block can be used to read frame-based data. When using this block a setup block is not required.

Speedgoat recommends this driver block for the following case:

Acquisition rate of analog inputs required to be higher than the model sample rate. Using DMA, the IO106 I/O module supports an acquisition rate of up to 200 KSPS (kilo-samples per second) per channel. For example, for a sample acquisition rate of 150 kHz, and a model sample rate of 30 kHz, the frame-size for each active channel would be 5. Each acquired frame is transferred by DMA to the target machine's RAM. The IO106 I/O module driver then issues an interrupt to pace the model execution at 30 kHz (the frame rate). In the model you could "throw away" 4 of the 5 samples but for example use the entire frame to store the data away.

In DMA mode, the model must contain an Interrupt Setup block that triggers a subsystem or the model. Refer to the block documentation for more information.

Ports

This driver block has n double-type output ports with the length of the frame size, where n is the number of selected analog input channels. Each port (signal) returns the analog value in volts.

Outputs

X (X is the analog channel number)

The value from analog channel X in volts.

Data Type: double

Parameters

Module ID

The Module ID has two functions:

It defines the logical connection between the Setup block and its I/O blocks
It also informs the auto-search feature of the PCI Slot parameter. If only one I/O module of this type is installed, the Module ID must be set to 1. If n modules are installed, it must be in the range 1:n. Not all the I/O modules installed in the target machine need to be used. To see how each I/O module maps to a Module ID, use this Speedgoat API:
```
speedgoat.getIoInterfaces("TargetName", "mySpeedgoat")
```

PCI Slot (-1: auto-search)

There are two approaches for mapping this block to a specific I/O module installed in your target machine. All modules of the same type must be configured using the same method.

Auto-Search: with the default value -1 the I/O module will be automatically located in the target machine. If you have multiple modules of the same kind, the Module ID defines which module is associated with this block. To see how each I/O module maps to a Module ID, use this Speedgoat API:
```
speedgoat.getIoInterfaces("TargetName", "mySpeedgoat")
```
Explicit Addressing: to explicitly define the logical address of the I/O module in the target machine, you can provide the PCI bus and slot numbers as a vector: [bus, slot]. To determine these numbers, run the following command in the MATLAB command window:
```
speedgoat.getIoInterfaces("TargetName", "mySpeedgoat", "Advanced", true)
```
Note that the PCI address can change whenever an I/O module is added or removed – usually, auto-search is the best option.

Autocalibration

The autocalibration is enabled by default to obtain maximum measurement accuracy. The autocalibration function compensates for component aging and minimizes the effects of temperature on accuracy. The calibration normally takes approximately 2 seconds, so we recommend increasing the host-target communication time-out in the model configuration parameters to allow for this. The calibration is not re-executed during normal start/stop operation once the target application has been downloaded. All input channels are calibrated to a single internal voltage reference. Offset and gain error corrections for each channel are determined during the autocalibration process and are applied to each channel in real-time during data acquisition.

Warning: Disabling the autocalibration can cause wrong values after a change of the input range.

Input Range

The input range for all A/D channels. This driver does not allow different ranges for individual channels.

Input Coupling

Either Single-ended, Pseudo-differential or Differential.

Single-ended: For single-ended channels, each input signal is measured with respect to the common input return. That is, each channel reports the difference between the input signal voltage and the voltage present on the common input return. This configuration provides the maximum number of inputs channels but allows noise and other forms of interference on the common return line to appear in the signal measurement.
Pseudo-differential: In this mode the first channel is designated as the reference for all other channels, and it is sampled value subtracted from the sampled values of all other channels. With this arrangement, noise and interference on the common return line is essentially canceled, and the first input line can be used as a "remote sense" line for channels 1 to 31.
Differential: Each input channel has a dedicated associated reference level channel.

Number of Channels

Defines the number of channels to be acquired. The count starts with the first channel.

Inter-Module Synchronization

Select either Initiator (default) or Target. If Initiator is selected, A/D conversions are initiated by this module and the module outputs a pulse train to optionally trigger other IO106 I/O modules where "Inter-Module Synchronization" is set to Target. The pulse train is sent on the I/O connector SYNC I/O pin. Ground is on the SYNC RTN pin (see the I/O pin mapping section for pin numbers).

If your target machine contains a single IO106 I/O module, then Initiator must be selected. If Target is selected, the module itself does not start its A/D conversions, but instead triggers them using a pulse train from another IO106 I/O module where "Inter-Module Synchronization" is set to Initiator. The pulse train is received on the SYNC I/O pin (ground is on the SYNC RTN pin). With this setting, there must be at least one other IO106 I/O module present with "Inter-Module Synchronization" set to Initiator, and the modules' SYNC I/O and SYNC RTN pins must be physically wired together (SYNC I/O to SYNC I/O, SYNC RTN to SYNC RTN). To use this feature with more than two IO106 I/O modules, all SYNC I/O pins and all SYNC RTN pins must be wired together (see the I/O pin mapping section for pin numbers). Exactly one IO106 I/O module must be set to Initiator and all the others to Target.

Frame Size, Sample Rate and Sample Time

Parameter dependency is as follows: frame size = sample time × sample rate. By defining two parameters, an equation will determine the third parameter automatically, provided that parameter value for the third parameter is set to -1.

Example: "Frame Size" of 32 and "Sample Rate" of 44100 and specifying "Sample Time" as -1. "Sample Time" is computed automatically to be 0.0007256 seconds. In other words, this model would execute every 0.0007256 seconds, which is every 32 samples at 44 kHz.

Frame Size

The number of samples per frame. An interrupt occurs each time the I/O module acquires a frame.

ADC Clock

The frequency at which the samples are taken. This parameter is in Hertz, and must be between 763 and 200000 Hz (763 Hz to 200 kHz). Note: The ADC clock is calculated internally by dividing the base clock on the module by an integer value. This defines the available frequencies. The calculation is depicted on the right hand side of the sample clock field (base clock / clock divider = sample clock).

Sample Time

The time between frame completions. Note: Sample time can only be a multiple of ADC clocks.

Documentation