Carel MPXPRO User Manual page 54

ENG
PL3 represents the alarm activation delay after exceeding the LOP
threshold. When the alarm is activated, the following occur:
• message 'LOP' shown on the display;
• the buzzer is activated.
The alarm features automatic reset when the evaporation pressure rises
above the threshold PL1.
PL3 = 0 ==> LOP alarm disabled
Manual valve positioning from supervisor (parameters
only visible on the supervisor)
Par. Description
PMP Enable manual expansion valve
positioning
0 = disabled; 1 = enabled
PMu Manual valve position
PMP is used to enable/disable manual positioning of the valve.
• PMP = 0: manual positioning disabled;
• PMP = 1: manual positioning enabled.
If manual positioning is enabled, this is used to set the manual opening
of the electronic valve. The value is expressed in steps for stepper valves,
and as a % for PWM valves.
Enabling high current valve driving
Par. Description
Phc Enable high current valve driving
0 = disable; 1 = enable
Set Phc to 1 when E3V45 or higher valves are used
• Phc = 0: high current disabled;
• Phc = 1: high current enabled.
Read-only variables
Par. Description
PF Valve opening steps (supervisor)
SH Superheat
PPU Valve opening percentage
tGS Superheated gas temperature
tEu Saturated evaporation temperature
PF: status variable that only displays, solely from the supervisor, the
current position of the electronic valve calculated by the controller.
System malfunctions may cause this value to be diff erent from the
eff ective position of the valve. Not used with PWM valves.
SH: status variable that only displays of the superheat value calculated by
MPXPRO and used to control of valve.
PPu: status variable that only displays the electronic valve opening as a
percentage, for both stepper and PWM valves.
tGS: status variable that only displays the evaporator outlet temperature
read by the corresponding probe (advanced parameter /Fd).
tEu: status variable that only displays the saturated evaporation
temperature calculated by the corresponding evaporation pressure
probe or read directly by the NTC probe (advanced parameter /FE).
PWM valve modulation period (parameter Po6)
Par. Description
Po6 PWM expansion valve Ton + Toff period
This represents the modulation period (in seconds) for the PWM
electronic expansion valve only (DC/AC). The opening of the PWM valve,
MPXPRO - + 0300055EN rel. 1.0 30/08/10
Def Min Max UoM
0 0 1 -
- 0 600 step
Tab. 6.j.e
Def Min Max U.M.
0 0 1 -
Tab. 6.j.f
Def Min Max UoM
- 0 - step
- - - K
- - - %
- - - °C/°F
- - - °C/°F
Tab. 6.j.f
Def Min Max UoM
6 1 20 s
Tab. 6.j.g
54
performed based on the PID parameters, refers to the period Po6 (in
seconds) and not to the maximum 480 steps for opening the stepper
valve. All the remarks made for the stepper valve can thus apply to the
PWM valves, considering these diff erences.