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Operation / SettingRPMAndSpeedReadings

Setting up internal/external RPM and vehicle speed readings

The DASH2 can display RPM and vehicle speed data from two different sources: Either from vehicle sensors wired directly to the DASH2 inputs (termed “internal” or DASH2 inputs), or via the output from an external data logger (termed “RS232” inputs). If the DASH2 is always used with a data logger, it is better to configure the unit to use the RPM output from the data logger so that a high level RPM input can be used. The vehicle speed output from the data logger would also give a more accurate input to the DASH2, but would only be present when the GPS signal is valid. The odometer and trip counter only use the pulse input from the “internal” vehicle sensor, so if the DASH2 is set up to use only the external speed input the odometer will not function. When RS232 speeds are enabled, the odometer updates in the same way as for the internal speed input, when used this way, the unit must be set up for a minimum of 400 pulses per mile. Otherwise the odometer readings will become inaccurate. For road legal applications the DASH2 must be used with a wheel speed input to measure vehicle speed and enable operation of the odometer and trip meter.

Configuring the DASH2 to read both input sources for RPM or vehicle speed simultaneously should be avoided. This can lead to information on the screen becoming unstable due to conflicting data being read from the two sources. The RPM and vehicle speed sources are selected from main menu item 6; “Speedo and RPM”, followed by selecting yes/no for “RS232 RPM” / “DASH2 RPM” and “RS232 speed” / “DASH2 speed”, where RS232 input refers to “external” data from a logger and “DASH2” input refers to “internal” sources from vehicle sensors connected directly to the DASH2.


1. Without a data logger connected: Use vehicle sensors to provide “internal” inputs to DASH2. RS232 inputs may be left enabled; with no signal present on these channels they will cause no disruption to normal operation

2. Road car with data logger: Internal wheel speed input, otherwise there will be no odometer. Internal RPM if available, otherwise external through data logger

3. Race car with data logger: External speed and RPM from data logger

To set the correct scaling and configuration of the RPM input, please refer to the DASH2 configuration software.

Page last modified on August 03, 2009, at 02:26 PM