7) Setting other system parameters
These are the parameters that normally do not need to be changed. The lock code to
access them is 155.
•
SC, calibration offset. The parameter is used to make the input offset to
compensate the error produced by sensor. e.g. if the temperature displays 2.0 C
in ice water mixture, set SC=-2.0 will make the display to shown 0.0 degree.
•
Out, Output power reduction. It is expressed as a percentage value. This
function will allow you to control the maximum output power delivered by the
heater in your cooker, for example, if you set Out=50 and your heater is 1000
watts, the output will use 50% of the 1000 watts as the full output. It thinks the
1000W heater as a 500W heater. When the PID algorithm determines 50% output
value, the actual power output will be 250 watts. This function can be used in two
situations.
1) When you have a very powerful heater and using a very small pot of water to
cook, for example, an 1800 watts heater with a one litter (1 qt) pot of water. The
heater is too powerful for the small water volume. The moment it is on, it releases
too much energy to cause the temperature to overshoot. Although it is still
possible to stabilize the temperature with proper PID parameters, it is much easier
to control if you limit the maximum output to 25%. Ideally, an optimized
temperature control system should consume about 25 % of the heater power at
set temperature (steady state), for example, if you found out that only 50 watts of
energy is needed to maintain the temperature at 60 C (141F), ideally you should
use only 200 watts heater for the job. Too much power will make the system over
react too quickly. Too little power will make the system too slow in response. By
using the OUt function, you can make the 1600 watts heater to act as a 200 watt
heater for stable temperature control.
2) When the cooker consumes more power than controller can handle, for
example, if you have a 15 A , 120V AC heater and your cooker contains more than
38 liter (10 gallon) of water. It might take more than 90 minutes of full power
heating for controller to heat up the pot. Long time of full power operation might
cause the controller to over heat. You can set the output to 80%. It will prevent the
controller from over heat by staying a full power too long. For details, please see
Appendix 1.
•
C-F, Display unit setting. You can set the display either Celsius or Fahrenheit.
When changing the display unit, the temperature setting and P constant will be
automatically converted.
•
TK, Timer setting. The timer function can be turned off by user.
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