Carel EVD Evolution Twin - Programmable control configuration; Direct;reverse control - Tens of thousands; AUX control - Thousands; Controlled value - Tens

ENG
“EVD Evolution TWIN” +0300006EN - rel. 2.6 - 31.01.2019
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Note: the control error is the result of the dierence between the set
point and the measurement:
setpoint error
PID
measure
Direct operation: error = measurement - set point
Reverse operation: error = set point - measurement
Programmable control conguration
Important: for the explanation of the HiTcond (high condensing
temperature), reverse HiTcond protectors and the “Modulating thermostat”
auxiliary control function, see Appendix 2.
Each digit in the “Programmable control conguration” parameter has a
special meaning, depending on its position:
POSITION DESCRIPTION NOTE
Tens of thousands (DM) Control: direct/reverse Select type of control
action: direct/reverse
Thousands (M) Auxiliary control Selection any auxiliary
control or protector
used for superheat
control
Hundreds Do not select -
Tens Controlled value Select the type of
controlled physical
value (temperature,
pressure…)
Units Measurement function Select the function for
calculating the value
controlled by the PID
(measurement)
Tab. 5.a
Direct/reverse control – Tens of thousands
Value Description
0 PID in direct control
1 PID in reverse control
2,….9 -
AUX control - Thousands
Value Description
0 None
1 HITCond protection
2 Modulating thermostat
3 HiTcond protection in reverse
4,….9 -
Hundreds – DO NOT SELECT
Controlled value - Tens
Value Description
0 Temperature (°C/°F), absolute
1 Temperature (K/°F), relative
2 Pressure (bar/psi), absolute
3 Pressure (barg/psig), relative
4 Current (mA) for control
5 Voltage (V) for control
6 Voltage (V) for positioner
7 Current (mA) for positioner
8.9 -
Measurement function - Units
Value Description
0 f1(S1)+ f2(S2)+ f3(S3)+ f4(S4)
1,….9 -
Programmable control input
The function assigned to each input is dened by parameter - “Programmable
control input”. The parameter has 16 bits and is divided into 4 digits, as
described in “Programmable control conguration”, corresponding to the 4
probes, S1, S2, S3, S4.
POSITION DESCRIPTION
Thousands Function of probe S1
Hundreds Function of probe S2
Tens Function of probe S3
Units Function of probe S4
Value Input function
00
1 + Sn
2 - Sn
3 + Tdew (Sn)(*)
4 - Tdew (Sn)
5 + Tbub (Sn)(**)
6 - Tbub (Sn)
7,8,9 -
(*): Tdew() = function for calculating the saturated evaporation temperature
according to the type of gas.
(**): Tbubble = function for calculating the condensing temperature.
B
C
Enthalpy [kJ/kg]
Pressure [MPa]
A
DE
F
Fig. 5.o
Key:
TA Saturated evaporation temperature = Tdew
TB Superheated gas temperature = suction temperature
TB – TA Superheat
TD Condensing temperature (Tbubble)
TE Subcooled gas temperature
TD – TE Subcooling
Options/ programmable control set point
Note:
- if Control = Programmable special control, the setting of the
“Programmable control options” parameter has no aect;
- if Control = “Programmable positioner”, the settings of the “Programmable
control options” and “Programmable control set point” parameters have
no aect.
The physical value measured is assigned to the individual probes S1 to S4 by
the “Programmable control options” parameter. The parameter has 16 bits and
is divided into 4 digits, as described in “Programmable control conguration”,
corresponding to the 4 probes, S1, S2, S3, S4. The control set point si sets to
the “Programmable control set point” parameter.
POSITION DESCRIPTION
Thousands Function of probe S1
Hundreds Function of probe S2
Tens Function of probe S3
Units Function of probe S4
Value Input function
0 None
1 Suction temperature
2 Evaporation pressure
3 Evaporation temperature
4 Condensing pressure
5 Condensing temperature
6 Temperature (modulating thermostat)
7,8,9 -