Carel PVPRO - 1. Introduction to Floating Suction and Smooth Lines; Smooth Lines on MPXPRO: How It Works

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+030220575 - 1.1 - 04.12.2014
ENG
Fig. 1.a
1.1 Smooth lines on MPXPRO: how it works
The main target of the Smooth lines function, available on MPXPRO version 3.2 and higher, is to keep the
control temperature very stable around the set point, avoiding frequent ON/OFF cycles of cooling request.
The parameters involved in the Smooth lines confi guration are listed in the following table:
Parameter name Menu Description Visibility
St CtL Control set point PVPRO & User interface
rd CtL Control diff erential PVPRO & User interface
P3 Eud Superheat set point PVPRO & User interface
PHS Eud Positive SH off set PVPRO & User interface
PLt Eud Off set below set point for cut-off PVPRO & User interface
PSI Eud Integral time PVPRO & User interface
PSM Eud Enable function PVPRO & User interface
PSP Eud Proportional coeffi cient PVPRO & User interface
PSd - Derivative time PVPRO
TSH - Superheat threshold PVPRO
FSt - Superheat averaging time window PVPRO
Tab. 1.a
The function works as follows: when the control temperature reaches the set point + half of the diff erential,
the control is not stopped, and a special PID algorithm increases the working superheat set point in order
to modulate the expansion valve. This special algorithm works until the control temperature exceeds St –
PLt.
1. INTRODUCTION