EVCO EC6708 - Manual (Page 9)

Every Control S.r.l.
Via Mezzaterra 6, 32036 Sedico Belluno ITALY • Phone 0039-0437-852468 (a.r.) • Fax 0039-0437-83648 • [email protected] • www.everycontrol.it
9
FUNCTIONING
Preliminary informations - Suction pressure regulation
PRELIMINARY INFORMATIONS
After derived the connections (see the chapter Electrical connection on
the page 51), the instrument reproposes the last setting stored.
Keeping pushed for two seconds at least the ON STAND-BY key the
instrument turning on (status ON) or turning off (status STAND-BY),
except during the setting procedures.
During the status STAND-BY the display and the LED are turned off,
except the ON STAND-BY LED, all relay outputs are forced to the status
OFF, except the output Al1 and the analog output signal is 4 mA or 0 V.
During the status ON, in the course of the normal functioning the
instrument displays the pressure read by the suction probe.
If an alarm should be active the instrument displays the alarm code
flashing, for instance “EFAn”, the buzzer utters an intermittent beep,
the alarm LED flashes and the output Al1 gets activated (see the para-
graph Alarms on the page 46); pressure on the down key during an
alarm permits to silence the buzzer but does not modify the outputs Al1
and Al1 status.
SUCTION PRESSURE REGULATION
Suction pressure regulation happens through the compressors.
The instrument activates the compressors (it loads power steps) with
sequence when the pressure read by the suction probe rises above the
working setpoint of the “neutral zone” value and it deactivates them (it
unloads power steps) in sequence when the pressure read by the
suction probe falls below the working setpoint of the “neutral zone”
value.
The parameter r A establishes the kind of regulating action that the
instrument must manage: it is function of the pressure read by the
suction probe (in this case when the pressure read by the suction probe
is above/below the working setpoint of the “neutral zone” value the
instrument loads/unloads power steps) ...
or function of the pressure read by the suction probe and of the direc-
tion of the pressure read by the suction probe (the same action saw in
the previous case but when the pressure read by the suction probe is
above/below the working setpoint of the “neutral zone” value and it is
going towards the “neutral zone” the instrument does not load/unload
power steps).
The instrument automatically computes which compressor to activate