Carel Hecu CO2 - 6.9 Generic Functions Overview

34
ENG
Hecu CO
2
+0300085EN rel. 2.2 - 07.05.2019
Summary of RPRV valve inputs/outputs and parameters
Screen Description
Analogue inputs Bab66,
Fha01
RPRV receiver pressure probe
Digital inputs Baadf,
Fha05
RPRV valve alarm
Analogue outputs Bad03,
Fha07
RPRV valve output
Digital outputs --- ---
Parameters
Set Fhb21 Enable RPRV valve management
Control Fhb25 CO
2
receiver pressure set point
Proportional gain for proportional + integral
RPRV valve control
Integral time for proportional + integral RPRV
valve control
Parameters
Safety features Fhb22 Minimum RPRV valve opening with unit ON
Minimum RPRV valve opening with unit OFF
Fhb23 RPRV valve opening at start-up during pre-po-
sitioning
Pre-positioning duration
Fhb24 Maximum RPRV valve opening
Maximum variation per second allowed for RPRV
valve output
Fhb26 HPV valve safety position
Fhb27 RPRV valve closing enabled when all line 1
compressors are off
RPRV valve closing delay when all line 1 com-
pressors are off
Fhb28 High receiver pressure alarm threshold
High receiver pressure alarm diff erential
High receiver pressure alarm delay
Type of high receiver pressure alarm reset
Enable compressor shutdown with receiver high
pressure alarm
Fhb31 Maximum RPRV valve control set point
Enable valve position (delay threshold)
Tab. 6.f
6.9 Generic functions
Hecu CO2 can use the free inputs / outputs and certain internal variables
for a number of generic functions.
The following generic functions are available for each board:
• 5 stages
• 2 modulation functions
• 2 alarms
Each function can be enabled/disabled by digital input and on the
user interface. The generic functions can be enabled and the related
parameters set in main menu branch Ff To be able to use the free inputs,
these fi rst need to be confi gured as generic from probes A to E (analogue
inputs) and general inputs from F to J (digital inputs), consequently a
maximum of fi ve analogue inputs and fi ve digital inputs can be used.
After having confi gured the generic probes, the associated variables
can be used as control variables, and the digital inputs as variables for
enabling the functions. As well as the generic probes and inputs, other
internal variables in the Hecu CO2 software can be used, depending on
system confi guration.
Examples:
for analogue variables:
• Suction pressure
• Condensing pressure
• Saturated suction temperature
• Saturated condensing temperature
• Suction temperature
• Discharge temperature
• % of compressors on
• % of fans on
• Superheat
• Subcooling
• Liquid temperature
• % of compressor request
• % of fan request
for digital variables:
• High suction pressure alarm
• Low suction pressure alarm
• High condensing pressure alarm
• Heartbeat
Each generic function can be assigned a unit of measure and a description.
Below are descriptions of how the three types of generic functions work.
Stages
Hecu CO2 can manage up to fi ve stage functions, with either direct or
reverse operation. In both cases, a set point and a diff erential can be
defi ned; operation of the corresponding output is shown in the fi gure
below, for both cases:
Regulation
variable
Setpoint
Di. Di.
Direct stage
Regulation
variable
Setpoint
Di. Di.
Reverse stage
Fig. 6.w
If a variable has been set to enable the function, the output connected to
the stage will be active when the enabling variable is active.
For each stage, there is a high alarm threshold and a low alarm threshold,
both absolute values. For each alarm, the activation delay and priority can
be confi gured.
Modulation
Hecu CO2 can manage two modulation functions, with either direct or
reverse operation. In both cases, a set point and a diff erential can be
defi ned; operation of the corresponding output is shown in the fi gure for
direct operation, with the cut-off function also enabled:
Regulation
variable
Setpoint
Hyster.
Direct modulation
Dierential
Min
(Cut-o
Value)
Max
Fig. 6.x
If a variable has been set to enable the function, the output connected
to the stage will be active when the enabling variable is active. For each
modulation function, there is a high alarm threshold and a low alarm
threshold, both absolute values. For each alarm, the activation delay
and priority can be confi gured. A minimum and maximum value of the
modulation output can also be set, and the cut-off function enabled,
which works as shown in the previous fi gure.
Alarms
Hecu CO2 can manage two alarm functions, by confi guring the digital
variable to be monitored, the activation delay, the priority and an
optional description. Each generic alarm function can be associated with
a digital output for activating external devices when the alarm occurs.
One example of a generic alarm functions is detecting gas leaks.