Carel srl: pCO Stage Controller
page 15
-10
42.25
10
17.96
30
8.31
-5
33.89
15
14.68
35
6.94
P22 - enabling of the probe of the external air (see figure 30)
This parameter enables the presence of a temperature probe of the external air and also allows to compensate the
probe 1 set-point. This parameter is present only if the probe 1 measures the temperature.
P23 - enabling of the probe 1 compensation
If the parameter P22 is active (P22=1), then it is possible to enable the procedure of compensation (cooling or er).
This procedure allows the setpoint variation of the primary circuit according to the values read by the external-air
temperature probe.
More precisely, a proportional quantity is added (or deducted) to the setpoint of the primary circuit according to the
selected compensation delta and with variation of the external air temperature between two values set by a setpoint
and a compensation differential. The maximum value that can be added (or deducted) to the setpoint of the primary
circuit is the same as the compensation delta (see fig. below).
setpoint compensation
differential compensation
external air
temperature
delta
compensation
circuit 1
setpoint
Fig. 15
P27 - number of probe 2 devices
This parameter allows to set the number of devices controlled by the probe 2. The devices can range from 0 to 11,
but this parameter depends also on the number of devices controlled by the probe 1 (parameter P4).
This mean that if no device controlled by the probe 1 is connected, the devices controlled by the probe 2 can be 11
at most, but, if the devices controlled by the probe 1 are 11, no device can be controlled by the probe 2.
P35 - enabling of fan inverter
The fan inverter can be enabled by this parameter. Enabling the control of fan inverter involves the selection of a
setpoint inverter (SI2) and a differential inverter (d4). When the value detected by the probe 2 is less than or the
same as the value of the setpoint inverter, the output dedicated to this device shows 0 volts. As the value detected
by the probe 2 deviates from the setpoint inverter, the analog output increases in proportion to the deviation until it
reaches the value of 10 volts when the measured value is equal to or greater than the setpoint in differential
inverter.
differential inverter
setpoint
inverter
value measured
probe 2
Volt
0
10
Fig. 16
P37 - enabling of the autostart
Allows the selection of the autostart procedure. When the procedure is enabled, if the unit is in the On state before a
black-out, after the black-out period, the On state is automatically restored.
P38 - type of freon
It allows to enable the type of freon used in the plant where the programme is installed.
0
No selection
1
R22
2
R134a
3
NH3 (ammonia)
4
R404a
P39 - °C or °F
Defines the unit of measure.
0
temperature in degrees Celsius (centigrades)
1
temperature in degrees Fahrenheit
When changing measurement system, automatic conversion of the values measured on the analog inputs is given.
Caution: the automatic conversion does not take place for the parameters. The user must update them when changing them
P40 - remote on/off selection
If the value of the parameter is 1, it is possible to use the third analog input to turn On or Off the unit:
open contact
→
unit off
closed contact
→
unit on
P41 - clock enabling
In case the clock board is used this parameter must be 1, otherwise it is not possible to have access to the clock
branch.
P42 - printer enabling