First it was the 2 Freescale sensors failed say a year apart, then 
thinking it was a particular model that was the problem, I bought 1 
Measurement specialties sensor as a trial, and after a near a year ago, 
and bought 2 more after a few months as spares. When one of the newer 
sensors failed, I began to question if there was another common issue 
causing the problem, and asked for help.

One item I turned up as ordering some new Freescale sensors. Several 
years ago, there was only one (at least that's what I thought) model 
sensor of this type/pressure available. Now there are 2. There is a 
MPX5010G, newer MPX5010G1. The newer is commercial/industrial qualified, 
and comes WITH LDFRM (What ever that is, I couldn't find).

As for the encapsulation, I had thought that as a possibility, adding 
considerable to the bonded mass of the original case, with thermal 
effects the concern. Protection from light physical damage, and moisture 
is main concern. The 3 wires are soldered (probably a no lead) to the 
terminals, carefully heat shrink individual wires (aircraft quality 
teflon), and then heat shrink over the 3 wires to the connector. I have 
opened the connector area, and no issues found there.

One possibility is, the ambient pressure port, and pressure ports could 
not, both, be pointed downward to drain any liquid, and the application 
could have a little moisture exposure. For the new encapsulation, I plan 
to provide both ports in the same direction, and mount in a downward 
direction to minimize liquid intrusion. I had questioned what the 
preferred orientation of the Measurement Specialties sensor, never 
received an answer. I mounted it horizontal, to minimize damage to the 
cable which comes out the opposite end from the male threaded port. A 
2nd issue, was I couldn't find an ambient port, and assumed the cable 
sheath provided the port. Again Specialty didn't respond.

YES NOPE9 wrote:
>> On Feb 17, 2010, at 3:36 PM, Carl Denk wrote:
>>
>> The Measurement Specialities sensors are $110, all I have to do is add
>> the connector. The Freescale sensors are $11 + $2 for brass nipple +
>> time to make the encapsulation and install the connectors. For the few
>> pieces, actual cost isn't so much of an issue, than reliability. Yes  
>> the
>> only failures are the sensors. I haven't done anything to the PIC  
>> board,
>> which has a PIC 18F1320. There is a Freescale MPX5010G sensor and a
>> LM335 temperature sensors also which have not been problems.
>>
>> On the reliability, the PIC is >> fiberoptic RS-485 >> PLC that  
>> manages
>> a 12.5KW standby generator, switching the fuel supply between the
>> natural gas well, propane and gasoline depending what is available. If
>> the generator fails, my basement could fill with water when the sump
>> pump doesn't have power. That's expensive. Oh, and the PLC does have a
>> water level switch on the sump, and will send an E-mail to my cell  
>> phone
>> in case of high water level.
>>     
>
>
> Sorry...... I am not clear on this ..... is the Freescale sensor  
> failing ?
> Are you substituting for the Freescale ?   Exactly which sensors are
> you having problems with ?
> I was thinking that the encapsulation might case problems.  But of
> course not if your substituted sensor model fails as well.
>
> Gus
>   
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