SCP SCIENCE
56
KeyPad
Version 1.0
TYPICAL HEATING RATES FOR DigiPREP HT
1st Step
When programming the fi rst 'time to temperature'
and the 'time at temperature' cycle, it is assumed that
the DigiPREP HT will begin the cycle from ambient
temperature. To enter the 'Time to Temperature' for
the fi rst step is a simple matter of using the graph
below.
Example:
Heat a DigiPREP HT block from 25
o
C (ambient)
to 300
o
C.
Solution:
From the graph, draw a line from 300
o
C across
to the curve representing the voltage that the
DigiPREP HT is connected to. (208 V is typical
in North America, 230 V in typical Europe). Draw
a line down from this point to the Time Scale.
Time to Temperature = at least 25 minutes.
2nd Step
When programming the additional ramp and
soak cycles, the Time to Temperature will depend
on the last temperature reached – i.e. the previous
setpoint. This becomes more complex, as the
heating rates for the DigiPREP HT depend on
both the Setpoint temperature and the ΔT. Tw o
equations are needed:
Equation 1: ΔT = T
fi nal – Tinitial
Equation 2: Time to Temperature = ΔT / rate
HT Typical Heating Rates (°C/min) vs
Setpoint temperature and ΔT
Δ T (°C)
Setpoint Temperature
25-50 50-225 225-350 350 +
0-25 1322
25-200 - 20 min 4 3
200-325 - - 8 4
325-425 - - - 5
HT - Typical Time to Temperature
0
50
100
150
200
250
300
350
400
450
500
0 20406080100
Time to Temperature (minutes)
Setpoint Temperature (deg C)
HT- Typical Time to Temperature
Setpoint Temperature (°C)
Time to Temperature (minutes)
208 Volts
230 Volts
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