This is a multi-part message in MIME format.
If you are looking for a response specifically from Jeffry, you can
disregard the below.
If you are looking for a response from someone who has PID'd a hottop, the
limitations for the number of ramps depends upon the PID you purchase. The
PXR3 has seven ramps which is three more than I usually use. You can of
course start the roast at whatever preheat temperature you desire.
The limits of the hottop have to do with the limits of its 'stock' ability
to add heat to a specific mass of beans. If we start with a moderate mass
of say 250 grams, with the element 'full on', the beans will heat up about
27 degrees per minute. You could program in a ramp that calls for say 40
degrees per minute, but the bottom line is you are only going to get 27.
One of the other limits is the response time - how fast it can go from say a
5 degree temp ramp to a 10 degree temp ramp to a 20 degree temp ramp.
Again, say we start with our 250 grams of beans "sitting" at 310 degrees -
not heating, just holding at 310. If we then command 'full heat on' you'll
see the bean temperature rise similar to the below. Yes, it does take 90
seconds for the bean to go up 1 degree in that situation - and that's
because it takes time for the element to come up to heat, the air to come up
to heat, and the drum surface to come up to heat.
The bottom line is it doesn't matter whether you have an on/off switch, a
PID, or a computer control - the base unit is only capable of adding 'so
much heat' to a given bean mass in a given mount of time.
[mailto:homeroast-admin] On Behalf Of Jeremy DeFranco
Sent: Saturday, January 20, 2007 1:56 PM
Subject: +Hottop- Question for Jeffrey Pawlan
I have a few questions I would appreciate your opinions on:
1st, what are the limitations of PIDing a Manual Hottop for profile control?
2nd, What is your take on the new programmable Hottop for attaining profile
Thanks in advance, Jeremy