Doc. No.:
560001 EG
Page:20
Ed.1" 08-2014
From ser. no.:
ENGLISH
cc: Continuous cycle duration
This is the time (in hours) during which the compressor operates continuously to lower the temperature, even below the set point.
With cc=0 => the continuous cycle is disabled. The controller exits the continuous cycle procedure after the time set for parame-
ter cc has elapsed, or upon reaching the minimum specifi ed temperature (see the minimum temperature alarm, parameter AL).
Default: cc=0 (hours).
Note:
if control with two compressor steps is selected (with or without rotation, ‘H1 or H5’= 12 or 13), the continuous cycle acts
on both steps
c6: Alarm bypass after continuous cycle
This is the time (in hours or minutes) for which the temperature alarm is deactivated after a continuous cycle. If the temperature
of the refrigeration unit, after the continuous cycle, falls due by inertia below the minimum temperature (set point – AL), the
activation of the low temp. alarm is delayed for the time c6.
Default: c6=2 (hours).
Warning: remember that at the minimum specifi ed temperature (see the minimum temperature alarm, parameter AL) the
continuous cycle is forced OFF and deactivated.
Parameter ‘c6’ may be expressed in hours ‘dC1’ = 0’ (default) or minutes ‘dC1’=1’.
c7: Maximum pump down time
This parameter determines, depending on the setting of parameter c10, the maximum time in minutes by which the circuit must
reach the required low pressure value in pump down operation (c10=0), or the compressor operating time after the closing of the
pump down valve in case of pump down operation by time (c10=1). The pump down valve must be connected to the auxiliary
output, setting the relevant parameter (H1 or H5).
Pump down by pressure (c10=1):
When reaching the maximum pump down time, the compressor stops and the Pd alarm is activated, which disables the compressor
autostart function (see parameter c9) with the pump down valve closed, on the “high pressure” request from the pressure switch.
The compressor remains OFF until the controller requires cooling. When reaching the set point, a pump down procedure is run and
the alarm is
automatically reset if the low pressure is reached within the time c7.
Low pressure is monitored by connecting the low pressure switch to one of the two digital inputs and setting the parameter A4, A5
or A9.
Pump down by time (c10=1):
When the compressor operating time c7 is reached after the closing of the valve, the compressor is stopped, irrespective of the low
pressure reading, and the Pd alarm is deactivated. In any case, the compressor is stopped when reaching the low pressure.
In this case, autostart in pump down is disabled. Default: c7 =0 => pump down disabled.
c8 : Compressor start delay after opening of PD valve
This parameter determines after how many seconds from the opening of the pump down valve the compressor starts. It is useful
to avoid activating the LP alarm unnecessarily.
The low pressure alarm (LP), with valve open and compressor ON, is activated by the opening of the pressure switch. This alarm
stops the compressor and is reset automatically.
Starting from July 2007 parameter c8 has been set to 0 and is not visible in the controllers distributed. The function relating to c8
can still be used, however it must be stressed that in certain conditions, during the time c8 (alarm from digital input, probe alarm,
on/off ), the pump down valve may remain open.
c9: Enable autostart function with PD operation (active when C7=6)
If parameter c9 is set to 0, the system will perform a pump down cycle each time the pump down valve closes. If the parameter
is set to 1, on the other hand, the system will perform a pump down cycle each time the pump down valve closes and on each
successive request from the low pressure switch when there is no cooling requirement (autostart situation). The activation of a
compressor autostart cycle in pump down is signalled by the message ‘Ats’. This message is reset automatically on the next correct
pump down cycle. The autostart function is disabled if Pd alarms are active or if pump down by time is selected.
Note:
the autostart function is disabled in the off status and if the controller has been switched on but the compressor has not yet been
activated (after the fi rst activation of the compressor, the autostart function, if selected, will be always active).
Default: c9=0 => only one pump down cycle is run whenever the pump down valve is closed.
c10: Select pump down by pressure or by time
This parameter determines if the pump down procedure must end following the activation of the low pressure switch, or after a set time. In
this case, after the valve closes, the compressor works for time c7 or until the low pressure value is reached. When this time has elapsed, the
compressor is stopped, irrespective of the status of the low pressure input.
The Pd alarm (pump down ended by timeout) and the compressor autostart function in pump down are disabled
Default: c10=0 => pump down by pressure.
c11: Second compressor delay
This parameter determines the delay of the second compressor, compared to the main compressor, during start-up (‘H1 or
H5’=7). Vice-versa, the two compressors are stopped at the same time.
If two compressor steps have been selected (‘H1’=12, 13), the parameter c11 represents the delay for the activation of the second
step from the fi rst.
Important:
select the auxiliary output as a delayed compressor or second compressor step using parameter ‘H1 or H5’. Default:
c11=4 => 4 second delay.
