ChannelSkewMode (Data Acquisition Toolbox)

Specify how the channel skew is determined

Description

For simultaneous sample and hold (SS/H) hardware, ChannelSkewMode is None. For scanning hardware, ChannelSkewMode can be Minimum, Equisample, or Manual (Keithley and National Instruments only). SS/H hardware includes Agilent Technologies devices and sound cards, while scanning hardware includes most Measurement Computing, Keithley, and NI boards. Note that some supported boards from these vendors are SS/H, such as ComputerBoard's DAS4020/12.

If ChannelSkewMode is Minimum, then the minimum channel skew supported by the hardware is used. Some vendors refer to this as burst mode. If ChannelSkewMode is Equisample, the channel skew is given by [(sampling rate)(number of channels)]^-1. If ChannelSkewMode is Manual, then you must specify the channel skew with the ChannelSkew property. For some vendors, ChannelSkewMode is automatically set to Manual if you first set ChannelSkew to a valid value.

Note If you want to use the maximum sampling rate of your hardware, you should set ChannelSkewMode to Equisample.

Characteristics

Usage
AI, Common

Access
Read/write

Data type
String

Read-only when running
Yes

Usage	AI, Common
Access	Read/write
Data type	String
Read-only when running	Yes

Values

Agilent Technologies and Sound Cards

{None}
This is the only supported value for SS/H hardware.

`{None}`	This is the only supported value for SS/H hardware.

Keithley and National Instruments

{Minimum}
The channel skew is set to the minimum supported value.

Equisample
The channel skew is given by [(sampling rate)(number of channels)]^-1.

Manual
The channel skew is given by ChannelSkew.

`{Minimum}`	The channel skew is set to the minimum supported value.
`Equisample`	The channel skew is given by [(sampling rate)(number of channels)]^-1.
`Manual`	The channel skew is given by `ChannelSkew`.

Measurement Computing

{Minimum}
The channel skew is set to the minimum supported value.

Equisample
The channel skew is given by [(sampling rate)(number of channels)]^-1.

`{Minimum}`	The channel skew is set to the minimum supported value.
`Equisample`	The channel skew is given by [(sampling rate)(number of channels)]^-1.

Example

Create an analog input object for Keithley's KPCI-3108 board and add eight channels.

ai = analoginput('keithley',10);
addchannel(ai,0:7);

Using the default ChannelSkewMode value of Min and the default SampleRate value of 1000, the corresponding ChannelSkew value is

```
ai.ChannelSkew
ans =
  1.0000e-005
```

To use the maximum sampling rate, set ChannelSkewMode to Equisample.

ai.ChannelskewMode = 'Equi';
ai.Samplerate = 100000/8;

See Also

Properties

ChannelSkew, SampleRate

ChannelSkew ClockSource