I 'think' this is probably associated with transmission shifting. So I understand that the signals must arrive in a timely fashion, but why the requirement for a special 'black box'? Can't they anticipate the circuit delays?
I 'think' this is probably associated with transmission shifting. So I understand that the signals must arrive in a timely fashion, but why the requirement for a special 'black box'? Can't they anticipate the circuit delays?
Brian
LVDT position measuring is based on a primary coil (oscillation and excitation ) and secondary (measuring)coils .The trouble is you need to sync the excitation to avoid standing waves and you need to keep cables short and shielded to avoid the different cables of each sensor to influence one anothor...
The main electronic boxes can only eat either digital or analogue signals ...the LVDT needs to be excited with a very precise signal not just a 12Vsupply to be able to feed back good signal...the electronic box exactly does this and feeds forwarward the analogue siganl to the ecu or in case of less critical applications it could do so via CAN.
even 30 or 40 years ago I was more or less surrounded by LVDTs
but AFAIK I have never seen an LVDT that was not DC in - DC out
granted you might still need to do some interfacing
if ever I was chasing some special linear position transducer eg an LVDT my boss would beg for 'DC in - DC out'
LVDTs with DC in DC out are simply an LVDT with integrated signal conditioning. This means the sensor is bulkier because it contains these extra electronics. This is obviously not ideal for an F1 installation.
I'd imagine external conditioners could be better performing in terms of temperature compensation and linearity because they are not bound by the necessity to fit inside the sensor.
Tommy Cookers wrote:even 30 or 40 years ago I was more or less surrounded by LVDTs
but AFAIK I have never seen an LVDT that was not DC in - DC out
granted you might still need to do some interfacing
if ever I was chasing some special linear position transducer eg an LVDT my boss would beg for 'DC in - DC out'
All LVDT's at the most fundamental level are AC input with a differential AC output. Any LVDT that is not this just has extra signal conditioning (often built in making the sensor large) to make your life easier. The complexity of properly exciting and reading an LVDT is not trivial and requires some effort.
Why would you want the LIU-4? Well if you take care of the electronics right, you get a high quality and accurate position signal. +1. Running the electronics external to the sensor makes the sensor very small and compact. Big +2. Given we can now get a quality signal and fit the sensor in our application we get the benefits of a sensor design that is very robust and known for surviving harsh conditions. +3.
If you've ever designed a system needing timely, high resolution position information in a tight space then you see the beauty of this interface.
The most critical position measuring systems are going to be the same ones using dual gain servovalves. These are advertised as being gear selector drum positioning, throttle control, and clutch control. Makes sense. I expect there are more.
