Powerlinc 1132 time accuracy resolution
- Thread starter Xymox
- Start date
Xymox
Member
Also....
I just checked my modded 1132CU accuracy. I have not set it in 4 moths.
It has gained a solid second. I checked carefully making sure my computer was very updated to the National bureau of Standards using Tardis.
I gained a second in 4 months.
This is a fairly stunning accuracy.
So it will be within 1 minute accuracy to about 20 years.
If this is the chip Smarthome put in the unit, I think this deserves "wow".
They also added shielding as I mentioned in this post...
The problem for me is,,,,,, I have become kinda attached to my modded module. I'm not sure I want to give it up !!... hahaha....
I do have the military spec version of the chip coming soon. It had a 4 month lead time from Mouser. Even better specs then the chip I have been describing. Not that any normal human would even need better then 1 minute in 20 year accuracy mind you... Still I want it anyway...
On a whole different project... I do have a different time base measuring device I have just restored...
1950 frequency counter
I just checked my modded 1132CU accuracy. I have not set it in 4 moths.
It has gained a solid second. I checked carefully making sure my computer was very updated to the National bureau of Standards using Tardis.
I gained a second in 4 months.
This is a fairly stunning accuracy.
So it will be within 1 minute accuracy to about 20 years.
If this is the chip Smarthome put in the unit, I think this deserves "wow".
They also added shielding as I mentioned in this post...
The problem for me is,,,,,, I have become kinda attached to my modded module. I'm not sure I want to give it up !!... hahaha....
I do have the military spec version of the chip coming soon. It had a 4 month lead time from Mouser. Even better specs then the chip I have been describing. Not that any normal human would even need better then 1 minute in 20 year accuracy mind you... Still I want it anyway...
On a whole different project... I do have a different time base measuring device I have just restored...
1950 frequency counter
Xymox
Member
I got the "new" 1132CU today...
I think I mis-interpreted what Smarthome said. I think I assumed more changes then they did.
Looking the the module the parts did not change and the layout did not change. In fact the only change was the addition of a RF absorbent material to the inside of the case which pressed directly against the RTC chip.
While at first this seems unlikely to have much effect, it is actually a pretty smart thing to do...
Most of the actual problems where the clock would become off by A LOT was due to RFI/EMI pickup by the VERY high impedance input on the RTC chip.
The material they used acts like a black hole for RFI. Literally. Its a big wide chunk of it too.
I don't have RFI susceptibility test equipment. Crazy gear thats as expensive as a house. So I improvised. I have access to a 20 watt output handheld VHF/UHF radio. Bringing the antenna right up against any electronics causes complete failure of any CPU based device. How close you get shows how well shielded its electronics are and how susceptible the design is to various frequencies.
The new modded module is WAY less susceptible then my modded unit !
I can of course still fry its brain by placing the antenna on the module, but my modded module looses it with the antenna 5" away.
This shows that the new 1132 is FAR less susceptible to RFI and RFI was the prime issue in the RTC getting its time scrambled.
Because it still uses a crystal circuit I don't expect it to as accurate long term as my modded unit with its hyper accurate time base.
HOWEVER I think Smarthome made a simple change, that anyone can do, and has seriously addressed the RFI issue.
Its now in my system along with my modded one. I am now logging its hourly drift like I did with my modded 1132. This will take a day to know what the daily drift is and will take longer to see what the long term drift is and if any unstable changes occur to the time keeping.
I should see a even and fairly predictable drift daily and a different yet predictable and smooth drift long term. Any sudden changes in time will indicate a problem.
While I was expecting more,,, this was prob my mistake. What they did do was innovative and easy for them to implement. It had a obvious and fairly dramatic effect in reducing RFI susceptibility.
I will report here my findings as we go.
I think I mis-interpreted what Smarthome said. I think I assumed more changes then they did.
Looking the the module the parts did not change and the layout did not change. In fact the only change was the addition of a RF absorbent material to the inside of the case which pressed directly against the RTC chip.
While at first this seems unlikely to have much effect, it is actually a pretty smart thing to do...
Most of the actual problems where the clock would become off by A LOT was due to RFI/EMI pickup by the VERY high impedance input on the RTC chip.
The material they used acts like a black hole for RFI. Literally. Its a big wide chunk of it too.
I don't have RFI susceptibility test equipment. Crazy gear thats as expensive as a house. So I improvised. I have access to a 20 watt output handheld VHF/UHF radio. Bringing the antenna right up against any electronics causes complete failure of any CPU based device. How close you get shows how well shielded its electronics are and how susceptible the design is to various frequencies.
The new modded module is WAY less susceptible then my modded unit !
I can of course still fry its brain by placing the antenna on the module, but my modded module looses it with the antenna 5" away.
This shows that the new 1132 is FAR less susceptible to RFI and RFI was the prime issue in the RTC getting its time scrambled.
Because it still uses a crystal circuit I don't expect it to as accurate long term as my modded unit with its hyper accurate time base.
HOWEVER I think Smarthome made a simple change, that anyone can do, and has seriously addressed the RFI issue.
Its now in my system along with my modded one. I am now logging its hourly drift like I did with my modded 1132. This will take a day to know what the daily drift is and will take longer to see what the long term drift is and if any unstable changes occur to the time keeping.
I should see a even and fairly predictable drift daily and a different yet predictable and smooth drift long term. Any sudden changes in time will indicate a problem.
While I was expecting more,,, this was prob my mistake. What they did do was innovative and easy for them to implement. It had a obvious and fairly dramatic effect in reducing RFI susceptibility.
I will report here my findings as we go.
Xymox
Member
Even bigger Hmmm.....
Last nights midnight update from the RTC was exactly correct. In 24hrs it stayed right on time.
So....
Maybe the unit was still getting thermally settled in and not stable the fist day. Its possible.
I need time to evaulate it further. It may well be that its keeping damn near perfect time.
Last nights midnight update from the RTC was exactly correct. In 24hrs it stayed right on time.
So....
Maybe the unit was still getting thermally settled in and not stable the fist day. Its possible.
I need time to evaulate it further. It may well be that its keeping damn near perfect time.
SmartLabsMike
Active Member
Any more drift or has it been more consistent?
Xymox
Member
It has been very consistant. A slow, stable drift gaining a second or 2 a day. I do set back of the thermostat during my work day so the temp has varied from 69-72 at night and from 78-84 during the day.
I also think the initial 30 second jump was for some weird unknown reason as it has not been seen since.
So this looks good to me.
I wanted to get a good baseline of performance before doing any thing more involved testing wise. I still want to drop the module in the freezer to test its drift in a enviroment in a consumers garage during winter. This should be discussed in the manual because temp extremes will cause much higher drift. However it will be interesting to see how much.
My indoor humidity has varied quite a bit. With the ultra high impeadence of the xtal circuit it is reasonable to assume that humidity will increase capacitance on the pins/leads and trace paths. So some variation might occur. There was little drift at all so the variation from 80-90% and back to 15% seemed to make any difference..
We had storms while I have had the module. Lots of lighting. Lots of power line flicker. Even a loss of power. None of this seemed to effect the new 1132.
So, so far no news is good news.
I also think the initial 30 second jump was for some weird unknown reason as it has not been seen since.
So this looks good to me.
I wanted to get a good baseline of performance before doing any thing more involved testing wise. I still want to drop the module in the freezer to test its drift in a enviroment in a consumers garage during winter. This should be discussed in the manual because temp extremes will cause much higher drift. However it will be interesting to see how much.
My indoor humidity has varied quite a bit. With the ultra high impeadence of the xtal circuit it is reasonable to assume that humidity will increase capacitance on the pins/leads and trace paths. So some variation might occur. There was little drift at all so the variation from 80-90% and back to 15% seemed to make any difference..
We had storms while I have had the module. Lots of lighting. Lots of power line flicker. Even a loss of power. None of this seemed to effect the new 1132.
So, so far no news is good news.
Xymox
Member
At 4 hrs its still alive and it has lost 1 second. This is still a good result of about 4-5 seconds a day.
The real test for the module I cannot do easily. Injecting massive power line noise at various frequencies and power levels and see what happens. This is the only thing I could think of that might show something useful.
I am now getting into situations beyond what the module was designed for. It does seems to work perfectly under normal use as far as i saw.
The real test for the module I cannot do easily. Injecting massive power line noise at various frequencies and power levels and see what happens. This is the only thing I could think of that might show something useful.
I am now getting into situations beyond what the module was designed for. It does seems to work perfectly under normal use as far as i saw.
SmartLabsMike
Active Member
Xymox,
thank you for the testing and info.
thank you for the testing and info.
Xymox
Member
Your welcome
Im not done though.
After freezing the unit for 48 hrs at 11F it has _NOT LOST TIME_. This is kinda amazing. You would expect some drift based on temp. This did not occur.
So it seems that even if a consumer places the unit in a garage in winter it will still keep accurate time.
Now im going to keep track for many more weeks and make really sure its good to go and really see what the drift is.
Overall, your good to go with the mod.
Im not done though.
After freezing the unit for 48 hrs at 11F it has _NOT LOST TIME_. This is kinda amazing. You would expect some drift based on temp. This did not occur.
So it seems that even if a consumer places the unit in a garage in winter it will still keep accurate time.
Now im going to keep track for many more weeks and make really sure its good to go and really see what the drift is.
Overall, your good to go with the mod.
Xymox
Member
Its been 17 days now.
It has gained 15 seconds. Nothing weird and it has performed flawlessly. It has been doing all my timer based events.
Having 2 1132CU's has been very helpful. I divide the programming between 2 modules and this allows more multitasking to occur. I can run more stuff at once...
It has gained 15 seconds. Nothing weird and it has performed flawlessly. It has been doing all my timer based events.
Having 2 1132CU's has been very helpful. I divide the programming between 2 modules and this allows more multitasking to occur. I can run more stuff at once...
SmartLabsMike
Active Member
thank you for the update.
Xymox
Member
40 days have gone by and the improved 1132CU has not had a single issue. It has worked without flaw.
It has gained 28 seconds in 40 days. Thats .7 seconds a day. This is quite good considering its only a basic crystal without any temp regulation. That implies it will gain about 4 minutes a year.
I have only seen this very steady gaining of time, no sudden shifts or unexplained changes after more then a month.
My other 1132CU which I modified with a military strength temp compensated clock is still keeping hyper accurate time at about 1 second drift every 4 months.
It has gained 28 seconds in 40 days. Thats .7 seconds a day. This is quite good considering its only a basic crystal without any temp regulation. That implies it will gain about 4 minutes a year.
I have only seen this very steady gaining of time, no sudden shifts or unexplained changes after more then a month.
My other 1132CU which I modified with a military strength temp compensated clock is still keeping hyper accurate time at about 1 second drift every 4 months.
