On the 2 machines that I have tested (both dual boiler rotary pump models) the 1st reading always seems to be somewhere between 180 -185 while the 4th reading seems to be between 195 - 198 on a consistent basis. That being the case it would seem the "one shot stability" rating is highly dependent upon the machine's set point. Set points near 198 will have very small intra shot variances while set points like 203.5 will have large variances. This leads me to conclude that as it is currently defined and measured "one shot stability" seems meaningless.

Does this help?

first image is first shot performance in the morning

second is an overview of a series of shots in the evening

third is a closup of one of the shots








Sean

Sean,

what was your setpoint?

what was the temp at the 4th second?

were you following the WBC testing procedures?

thanks.

cinergi wrote:Sean,

what was your setpoint?

what was the temp at the 4th second?

were you following the WBC testing procedures?

thanks.

shot 2 was 202...4th second =202

the shot series was 204 (don't ask.. it was done for a reason)...4th second=~203

Shot 2...WBC as close to the letter as possible.
The bump in the curve at ~second 5 was control oscillation in the group, I was tuning the system.


shot series was prior to release of the standard


I can regularly get to within .5F of target with the new configuration of the machine.

Rise time is up to me for the most part now.

Sean

well, if you take the scace thermofilter out for 15 sec. then do a 2 sec. flush then put the p/f back in and start the shot I don't see how to get the 4th second up to the set point especially if the setpoint is high like 204. Seems like most machine profiles start out at somewhere in the 180-190 range and that greatly depends on how fast you are getting the p/f back in.

This is how my machine performs, "it is what it is" as the man said.

It has an active group (control)

At the time I didn't really care how it performed relative to the WBC standard (still don't) because I was tuning the controls.

I tested to the standard on the non-series shot to be able to make comparisons with another machine and the standard was available to use...that was all.

Do you have data to post?
perhaps I am not understanding your question.


Sean

cinergi wrote:well, if you take the scace thermofilter out for 15 sec. then do a 2 sec. flush then put the p/f back in and start the shot I don't see how to get the 4th second up to the set point especially if the setpoint is high like 204. Seems like most machine profiles start out at somewhere in the 180-190 range and that greatly depends on how fast you are getting the p/f back in.

Most machines do not provide good temp stability.
This is not a shock.

See Barry's comment above

What Malachi said...

lennoncs wrote:I can regularly get to within .5F of target with the new configuration of the machine.

This is as good as the Synesso. Doug Shannon who got a one group Synesso recently reports the same results. Sean, your active E61 group basically made it equivalent to the Synesso saturated group, in its bottom line temp performance, though the technology is different.

cinergi wrote:Why are just the 1st 3 readings thrown out? I have seen others throw out the 1st 8 - 10 readings like Schomer. This makes the most sense to me because looking at most profiles I see sharp temp increases during the 1st 8-10 seconds then it pretty much levels off. I would guess that this is due in part to thermometer lag, time to full pressurize and saturate the puck. Throwing out just the 1st 3 readings makes for mighty big stability readings.

Doug

Because the early rampup data is interesting. The temperature ramp is part of the process. No reason to throw out data just because it doesn't look pretty.

-Greg