Filter Channel

Overview

Filter channels can be configured to apply a chain of filters to the Primary Input channel.

Adding / Removing Filters

Use the and buttons to the bottom right of the Filter/Modifier list to add or remove filters from the list. The first item is the Filter Channel itself and can’t be removed.

Chained Filters

When there are multiple filters in a chain, Dash Design will insert hidden ‘modifier’ channels into the setup.

If the channel is used as the input to another output or a gauge then references shall be updated so that value at the end of the filter chain is routed to the output or gauge.

Filters

Minimum Since Reset

Outputs the minimum value of valid input values since the display was started / the filter was reset.

See Reset Triggers for details on the Reset Trigger and Reset Source options.

Maximum Since Reset

Outputs the maximum value of valid input values since the display was started / the filter was reset.

See Reset Triggers for details on the Reset Trigger and Reset Source options.

Average Since Reset

Outputs the average value of valid input values since the display was started / the filter was reset.

See Reset Triggers for details on the Reset Trigger and Reset Source options.

Value Reject

Rejects any input values that are below Minimum or above Maximum.

If out of range inputs are received then the value is not passed on to derived outputs or gauges.

Rate Reject

A filter that limits the rate of change of the input channel.

Data that changes faster than the rate limit is discarded. Called ‘Rate Filter’ in prior versions.

Rolling Minimum / Rolling Maximum / Rolling Average

Outputs the minimum/maximum/average value of the input value over a time window.

Update Period [ms]

Frequency at which the filter is calculated and will produce a value.

Increasing the update period will reduce memory requirements since the display must store less samples in the given time window.

Rolling Period [ms]

Range over which the rolling function is calculated (the window size).

Avoid excessively large windows with short update periods as these will require large amounts of memory in the display.

If the memory required for the window exceeds available resources, then the display setup may not function correctly.

Sample And Hold (Resample)

A filter that takes a single channel value sample and outputs that value for a predetermined time, before another sample is taken and output.

S&H Update Period [ms]

Frequency at which the input value is resampled.

Input Timeout Fallback

A filter that watches to see if an input channel is still being updated and if not, then a default value is sent in it’s place.

Typically used to define a replacement channel value when a CAN channel ceases to arrive as expected rather than just showing the last CAN value received.

Fallback Value

Value to output if the input times-out.

Timeout Value

Timeout, in milliseconds. If no value received after this period, the fallback value will be shown.

Error Text

Checks if a value is out of range to produce error text when in the out of range condition.

Comparison Value

Value for logic comparison with the input value (NOT Error Input).

Comparator

Logical comparison operator for comparing input value with the input value, as in:

'input value' <comparator> <comparison value>

e.g.

'input value' < 5

Error Text Option

Text that should be output to gauges if the error condition is active.

Error Input

Input channel that if non-zero, shall be used to put the channel into the error condition.

If an Error Input and a condition are specified then the result is the logical OR of the two conditions.

Reset Triggers

Many filters offer a Reset Trigger. This is specified in conjunction with a Reset Source.

Reset Source

Input Channel to reset the filter. The Reset Trigger option specifies how the Reset Source value is interpreted.

Reset Trigger

Select the condition under which the Reset Source should trigger a reset of the filter.

Any Edge

Any change in value of Reset Source shall reset the filer.

Falling Edge

Reset the filter when Reset Source reduces in value.

Rising Edge

Reset the filter when Reset Source increases in value.

Level: OFF

Reset the filter when Reset Source is zero.

Level: ON

Reset the filter when Reset Source is not zero.

Supported By Displays