Dual Helm Instrument Question

"I should know this but I ques

"I should know this but I question my knowledge at this stage of my life.

With dual helms I know that there is a different sending unit for these options. IF....one of the gauges ( temp ) is not working below, will the information displayed on top correct or is an impedence change occurring within the bad instrument giving a different reading. I will be upgrading both helms this winter but I have to live with poor but critical information until then. By the way the tachs are probably 700 rpm off but the new swing needle sync meter works great, at almost any speed you can HEAR the harmonics come together. If you check the gauge, you can really see it right on center. This is the only gauge I have SLIGHT faith in."

"Al:

It depends how the &#3

"Al:

It depends how the "bad" gauge fails. another variable is the style of the gauge (low resistance = full scale or the other way).

The bottom line not likely to maintain accuracy. This is based on most of the "failures" I've seen being due to bad connections. If one of the gauges is "out" of the circuit, you have a "dual" sender driving a single gauge. This equal bad reading.

You can check the www for your specific brand's details; I've looked at VDO and Teleflex data on the WWW. The typical teleflex sender used for the 'dual' install has half the resistance of a single unit sender, for a given point. this will sink twice the current thus 'satisfying' the need for each gauge at that point.

This is all simple OHM Law stuff and is all that's essential to understand the behavior.

If you have anymore specific questions, just provide the info available with them."