dixell XC642C User manual

Compressor racks controller
XC642C
Operating manual

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CONTENT
1. GENERAL WARNING ______________________________________________________ 3
1.1 Please read before using this manual ____________________________________________ 3
1.2 Safety Precautions _________________________________________________________ 3
2. GENERAL DESCRIPRION __________________________________________________ 3
3. FIRST INSTALLATION _____________________________________________________ 3
3.1 How to select the gas type _________________________________________________________ 4
3.2 How to set the range of the pressure probes ___________________________________________ 4
3.3 How to set the kind of display: relative or absolute pressure _______________________________ 4
4. USER INTERFACE ________________________________________________________ 5
4.1 Displaying ______________________________________________________________________ 5
4.2 Keyboard _______________________________________________________________________ 5
4.3 Icons __________________________________________________________________________ 6
5. HOW TO SEE AND MODIFY THE SET POINT ___________________________________ 6
5.1 How to see the set point of compressors ______________________________________________ 6
5.2 How to modify the set point of compressors ____________________________________________ 6
6. PARAMETERS PROGRAMMING _____________________________________________ 7
6.1 How to enter the “Pr1” parameter list _________________________________________________ 7
6.2 How to enter in parameters list “Pr2” _________________________________________________ 7
6.3 How to change parameter values ____________________________________________________ 7
7. HOW TO DISABLED AN OUTPUT ____________________________________________ 7
7.1 How to disabled an output during a maintenance session. ________________________________ 7
7.2 Output disabled signalling. _________________________________________________________ 8
7.3 Regulation with some outputs disabled. _______________________________________________ 8
8. RUNNING HOURS OF LOADS _______________________________________________ 8
8.1 How to display the running hours of a load. ____________________________________________ 8
8.2 How to reset the running hours of a load. ______________________________________________ 8
9. ALARM MENU ____________________________________________________________ 8
9.1 How to see the alarms_____________________________________________________________ 8
10. USE OF THE PROGRAMMING “HOT KEY “ ____________________________________ 9
10.1 How to program a hot key from the instrument (UPLOAD) ________________________________ 9
10.2 How to program an instrument using a hot key (DOWNLOAD) _____________________________ 9
11. KEYBOARD LOCKING _____________________________________________________ 9
11.1 How to lock the keyboard __________________________________________________________ 9
11.2 To unlock the keyboard ____________________________________________________________ 9
12. LIST OF PARAMETERS ___________________________________________________ 10
12.1 Plant dimensioning and type of regulation. ____________________________________________ 10
12.2 Others inputs configuration ________________________________________________________ 10
12.3 Display and Measurement unit _____________________________________________________ 11
12.4 Compressors regulation __________________________________________________________ 11
12.5 Liquid injection thermostat (Term. 25-26) _____________________________________________ 11
12.6 Alarms – compressor section ______________________________________________________ 11
12.7 Other _________________________________________________________________________ 12
13. CAPACITY VARIATION WITH SCREW COMPRESSORS _________________________ 12
14. THERMOSTAT FOR LIQUID INJECTION ______________________________________ 13
15. TYPE OF REGULATION ___________________________________________________ 13
15.1 NEUTRAL ZONE________________________________________________________________ 13
15.2 PROPORTIONAL BAND __________________________________________________________ 14
16. MOUNTING & INSTALLATION ______________________________________________ 15
17. ELECTRICAL CONNECTIONS ______________________________________________ 15
17.1 Probes connection_______________________________________________________________ 16

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18. RS485 SERIAL LINK ______________________________________________________ 16
19. TECHNICAL FEATURES___________________________________________________ 16
20. ALARMS LIST ___________________________________________________________ 16
20.1 Types of alarms and signalling managed _____________________________________________ 16
20.2 Alarm muting ___________________________________________________________________ 18
20.3 Alarm conditions – summary table __________________________________________________ 18
21. WIRING CONNECTIONS___________________________________________________ 20
22. PARAMETERS – DEFAULT VALUES ________________________________________ 20
1. General warning
1.1 PLEASE READ BEFORE USING THIS MANUAL
•This manual is part of the product and should be kept near the instrument for easy and quick reference.
•The instrument shall not be used for purposes different from those described hereunder. It cannot be
used as a safety device.
•Check the application limits before proceeding.
1.2 SAFETY PRECAUTIONS
•Check the supply voltage is correct before connecting the instrument.
•Do not expose to water or moisture: use the controller only within the operating limits avoiding sudden
temperature changes with high atmospheric humidity to prevent formation of condensation
•Warning: disconnect all electrical connections before any kind of maintenance.
•Fit the probe where it is not accessible by the End User. The instrument must not be opened.
•In case of failure or faulty operation send the instrument back to the distributor or to “Dixell S.p.a.” (see
address) with a detailed description of the fault.
•Consider the maximum current which can be applied to each relay (see Technical Data).
•Ensure that the wires for probes, loads and the power supply are separated and far enough from each
other, without crossing or intertwining.
•In case of applications in industrial environments, the use of mains filters (our mod. FT1) in parallel with
inductive loads could be useful.
2. General Descriprion
The XC642C is a controller for screw compressor racks, the main objective of controller is to hold the
controlled variable at constant value, this function is performed via compressor power control.
The controller survey the pression via 2 pression probe with 4÷20mA current output, while the regulation type
is ON/OFF.
Alternatively you can to use NTC or PTC temperature probes. The pression data are converted to
correspondent gas temperature value according to tables that are stored into controller.
The alarms management is performed by an alarm input for every user. The programming procedure is
simplified by HOT KEY use. The communication is performed via ModBus RTU protocol.
3. First Installation
At first installation, it’s necessary the following:
1. Select the kind of gas.
2. Set the range of the pressure probes.
In the following paragraph a short cut for the above operations.
Chapters 3.1 How to select the gas type and 3.2 How to set the range of the pressure probes will show in
detail these operations.

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3.1 HOW TO SELECT THE GAS TYPE
The controller has memorised the relation between temperature and pressure for some gases.
Default gas is: r404.
If another gas is used, act as in the following:
1. Enter the Programming mode by pressing the Set and DOWN key for 3s.
2. Select the “Pr2” parameter. Then enter the password 3 –2 1.
3. Select the FtyP, kind of gas, parameter.
4. Press the “SET” key: the value of the parameter will start blinking.
5. Use “UP” or “DOWN” to change the gas amount the following: . Select the gas among the following:
r22= R22; r404=R404A; 507=R507; 134=134; r717= ammonia.
6. Press “SET” to store the new value and move to the following parameter.
To exit: Press SET + UP or wait 30s without pressing a key.
NOTE: the set value is stored even when the procedure is exited by waiting the time-out to expire.
3.2 HOW TO SET THE RANGE OF THE PRESSURE PROBES
If a instrument with the following part number is used: XC642C – xxxxF, it is pre-set to work with pressure
probe with the following range:
Code Range
XC642C – xxxxA opp. xxxxE -0.5 ÷11 bar (relative pressure)
XC642C – xxxxB 0÷30 bar (relative pressure)
If the probes you’re using have a different range act as in the following:
To set the pressure range of the Probe 1 use the parameter::
PA04: Adjustment of read out corresponding to 4mA
PA20: Adjustment of read out corresponding to 20mA
Practically these parameters has to be set with the start and end scale of the probe range.
WARNING: set a value correspondent to absolute pressure. If the transducer measures relative pressure
increase the range of 1 bar.
E.I. PP11 relative pressure transducer, range -0.5÷11.0 bar. PA04=0.50; PA20=12.00.
PP30 relative pressure transducer, range: 0÷30bar. PA04=1.00; PA20=31.00.
How to do:
1. Enter the Programming mode by pressing the Set and DOWN key for 3s.
2. Select the “Pr2” parameter. Then enter the password 3 –2 1.
3. Select the PA04, adjustment of read out corresponding to 4mA, parameter.
4. Press the “SET” key: the value of the parameter will start blinking.
5. Set the lower value of the probe range (lower value +1 if the probe detects relative pressure).
6. Push the SET key to confirm the value. The PA20: adjustment of read out corresponding to 20mA
parameter will be displayed.
7. Set the higher value of the range (higher value +1 if the probe detects relative pressure).
8. Push the SET key to confirm the value. Next parameter will be displayed.
3.3 HOW TO SET THE KIND OF DISPLAY: RELATIVE OR ABSOLUTE PRESSURE
After setting the probe range by means of the PA04, PA20, parameters, it’s possible to select if the absolute
or relative pressure has to be displayed.
The controller is pre-set for RELATIVE PRESSURE displaying.
If the absolute pressure has to be displayed, act as in the following:

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1. Enter the Programming mode by pressing the Set and DOWN key for 3s.
2. Select the “Pr2” parameter. Then enter the password 3 –2 - 1.
3. Select by pushing the UP key the rELP parameter.
4. Push the SET to modify the value.
5. Set the AbS value and push the SET key to confirm it.
To exit: Press SET + UP or wait 30s without pressing a key.
4. User Interface
4.1 DISPLAYING
UPPER DISPLAY LOWER DISPLAY ICONS
Temperature Pressure
-Working loads
-Measurement unit
-Alarm or status Icons
4.2 KEYBOARD
SET To see or modify the set point. in programming mode it selects a parameter or confirm an
operation.
Alarm menu: By holding it pressed for 3s, the current alarm is erased.
o
oo
o(UP) To enter the Alarm menu.
In programming mode: it browses the parameter codes or increases the displayed value.
With Hot key inserted: it starts the Hot key programming procedure.
n
nn
n(DOWN)In programming mode: it browses the parameter codes or decreases the displayed value.
Manual restart of loads: By holding it pressed for 3s, it switches on again loads previous locked
by a safety digital input alarm.
e
ee
eCLOCK To display the loads running hours.
By holding it pressed for 3s the Maintaining menu is entered.
KEY COMBINATIONS
o
oo
o + n
nn
n To lock and unlock the keyboard.
SET + n
nn
nTo enter the programming mode.
SET + o
oo
o To exit the programming mode.

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4.3 ICONS
LED FUNCTION MEANING
ON Celsius degrees
ON Fahrenheit degrees
bar ON bar displaying
PSI ON PSI displaying
ON Load 1 on
Flashing Load 1 is waiting to start (1HZ). or digital input alarm for Load 1 (2Hz).
o Load 1 in maintenance status (2Hz).
ON Load 2 on
Flashing Load 2 is waiting to start (1HZ). or digital input alarm for Load 2 (2Hz).
o Load 2 in maintenance status (2Hz).
ON Load 3 on
Flashing Load 3 is waiting to start (1HZ). or digital input alarm for Load 3 (2Hz).
o Load 3 in maintenance status (2Hz).
ON Load 4 on
Flashing Load 4 is waiting to start (1HZ). or digital input alarm for Load 4 (2Hz).
o Load 4 in maintenance status (2Hz).
ON The Maintenance menu has been entered
Flashing One or more loads have been placed in maintenance status
ON Alarm is happening
ON All the stored alarms have been seen.
Flashing A new alarm has happened
5. How to see and modify the set point
5.1 HOW TO SEE THE SET POINT OF COMPRESSORS
1) Push and release the SET key;
2) The Lower display will show the “SEtC” label, will the Upper display will show its value.
To exit: push the SET key or wait for 30 without pressing any keys.
5.2 HOW TO MODIFY THE SET POINT OF COMPRESSORS
WARNING: before setting the target set points for the first time, check and, if necessary, modify the
type of freon (par. FtyP) and the default unit of measurement (par. dEU) for compressors and fans
PROCEDURE
1. Set the kind of freon by means of the FtyP parameter (see chapter 3.1 How to select the gas type)
2. Set the measurement unit (dEU par.).
3. Check and if necessary modify the set point limits (LSE and HSE par.).
1. Push the SET key for more than 2 seconds;
2. The Lower display will show the “SEtC” label, will the Upper display will show its value
flashing.
3. To change the Set value push the o
o o
o or n
nn
nwithin 30s.
4. To memorise the new value and pass to the fan set point push the SET key.
5. To change its value push the o
o o
o or n
nn
nwithin 30s.
To exit: push the SET key or wait for 30 without pressing any keys.

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6. Parameters programming
6.1 HOW TO ENTER THE “PR1” PARAMETER LIST
To enter the “Pr1” parameter list, user accessible, operate as follows:
1. Hold pressed the SET and DOWN key for 3s.
2. The controller displays the name of the parameter in the Lower display, its value on
the Upper display.
3. Press the “SET” key: the value of the parameter will start blinking.
4. Use “UP” or “DOWN” to change the value.
5. Press “SET” to store the new value and move to the following parameter.
To exit: Press SET + UP or wait 30s without pressing a key.
NOTE: the set value is stored even when the procedure is exited by waiting the time-out to expire.
6.2 HOW TO ENTER IN PARAMETERS LIST “PR2”
The “Pr2” parameter list is protected by a security code (Password).
SECURITY CODE is 321
To access parameters in “Pr2”:
1. Enter the “Pr1” level.
2. Select “Pr2” parameter and press the “SET” key.
3. The flashing value “0 --” is displayed.
4. Use o
oo
oor n
nn
nto input the security code and confirm the figure by pressing “SET” key.
5. Repeat operations 2 and 3 for the other digits.
NOTE: each parameter in “Pr2” can be removed or put into “Pr1” (user level) by pressing “SET” + n
nn
n. When
a parameter is present also in “Pr1” decimal point of the lower display is on.
6.3 HOW TO CHANGE PARAMETER VALUES
1. Enter the Programming mode.
2. Select the required parameter with o
oo
oor n
nn
n.
3. Press the “SET” key the value start blinking.
4. Use o
oo
oor n
nn
nto change its value.
5. Press “SET” to store the new value and move to the following parameter.
To exit: Press SET + UP or wait 15s without pressing a key.
NOTE: the new programming is stored even when the procedure is exited by waiting the time-out.
7. How to disabled an output
To disabled an output during a maintenance session means to exclude the output from the regulation.
7.1 HOW TO DISABLED AN OUTPUT DURING A MAINTENANCE SESSION.
1. Push the CLOCK key for 3s.
2. The LED’s of the first output is switched on, the Lower display shows the
“StA” label, while the Upper display shows the “On” label
if the first output is enabled, or the “oFF” label if the output is disabled for a maintenance section.
With compressor with more steps all the LED’s linked to the compressor and the valves are switched
on..
3. Select the output by pressing the UP or DOWN key.

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4. To modify the status of the output: push the SET key, the status of the output starts flashing, then
push the UP or DOWN to pass from “On” to “OFF” and viceversa.
5. Push the SET key to confirm the status and pass to the next output..
To exit: push the CLOCK key or wait 30 sec
7.2 OUTPUT DISABLED SIGNALLING.
If an output is disabled its led blinks (2 Hz)
7.3 REGULATION WITH SOME OUTPUTS DISABLED.
If some outputs are disabled they don’t take part to the regulation, so the regulation goes on with the other
outputs.
8. Running hours of loads
8.1 HOW TO DISPLAY THE RUNNING HOURS OF A LOAD.
The controller memorises the running hours of each load.
To see how long a load has been working follow this procedure:
1. Press and release the “CLOCK” key.
2. The led of the first output is switched on, the Upper Display shows the
“HUr” label, while the Lower Display shows the shows the running hours
of the first output.
3. To see the running hours of the following load press the UP key .
To exit: push the CLOCK key or wait 30 sec
8.2 HOW TO RESET THE RUNNING HOURS OF A LOAD.
1. Display the running hour according to the above procedure.
2. Select the load by pressing the UP key.
3. Push the SET key (immediately on the lower display the rSt label is displayed).
4. Hold pushed the key for some seconds till the “rSt” label starts flashing and the lower display shows
zero.
To exit: push the CLOCK key or wait 30 sec
NOTE: if the SET key is released within 2s, the controller reverts to display the running hours of the selected
loads.
9. Alarm Menu
The controller memorises the last 20 alarms happened, together with their duration..
To see the alarm codes see par. par. 20 Alarms list.
9.1 HOW TO SEE THE ALARMS
1. Push the o
o o
o key.
2. The last alarm happened is showed on the Upper display, while the
lower display shows its number.
3. Push again the o
oo
okey and the other alarm are displayed starting from
the most recent.
4. To see the alarm duration and push the SET key.
5. By pushing again the o
o o
o or SET key the next alarm is displayed.
Alarms erasing.
1. Enter the Alarm Menu.

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2. To erase the displayed alarm push the “SET” key till the “rSt” label will be displayed in the Lower
Display. NOTE the running alarms cannot be erased..
3. To erase the whole Alarm Menu, hold pressed the “SET” key for 10s.
10. Use of the programming “HOT KEY “
10.1 HOW TO PROGRAM A HOT KEY FROM THE INSTRUMENT (UPLOAD)
1. Program one controller with the front keypad.
2. When the controller is ON, insert the “Hot key” and push o
oo
okey; the "uPL" message appears followed
a by flashing “End”
3. Push “SET” key and the End will stop flashing.
4. Turn OFF the instrument remove the “Hot Key”, then turn it ON again.
NOTE: the “Err” message is displayed for failed programming. In this case push again o
oo
okey if you want to
restart the upload again or remove the “Hot key” to abort the operation.
10.2 HOW TO PROGRAM AN INSTRUMENT USING A HOT KEY (DOWNLOAD)
1. Turn OFF the instrument.
2. Insert a programmed “Hot Key” into the 5 PIN receptacle and then turn the Controller ON.
3. Automatically the parameter list of the “Hot Key” is downloaded into the Controller memory, the “doL”
message is blinking followed a by flashing “End”.
4. After 10 seconds the instrument will restart working with the new parameters.
5. Remove the “Hot Key”..
NOTE the message “Err” is displayed for failed programming. In this case turn the unit off and then on if you
want to restart the download again or remove the “Hot key” to abort the operation.
The unit can UPLOAD or DOWNLOAD the parameter list from its own E2 internal memory to the “Hot Key”
and vice-versa.
11. Keyboard locking
11.1 HOW TO LOCK THE KEYBOARD
1. Keep the o
oo
oand n
nn
nkeys pressed together for more than 3 s the o
oo
o
and n
nn
nkeys.
2. The “POF” message will be displayed and the keyboard is locked. At this
point it is only possible to view the set point or enter the HACCP menu.
11.2 TO UNLOCK THE KEYBOARD
Keep the o
oo
oand n
nn
nkeys pressed together for more than 3s till the “POn” flashing message appears.

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12. List of parameters
12.1 PLANT DIMENSIONING AND TYPE OF REGULATION.
oA1, oA2, oA3, oA4, oA4 Outputs 1- 4 configuration: by means of these parameters the plant can be
dimensioned according to the number and type of compressors and/or fans and the number of steps for
each one.
Each relay according to the configuration of the oA(i) parameter can work as:
-Compressor: oAi = cPr,
-Step: oAi = StP
-Injection liquid valve: oAi = Lin
-Alarm: oAi = ALr
-Not used: oAi = nu
NOTE: also the “FAn” value is present. This value must not be used..
COMPRESSORS CONFIGURATION
The regulation is always performed by the P1 Probe.
With step compressors the output of compressor has to be set before the output of the step.
ES. Compressor with 3 steps: oA1 = cPr, oA2= StP, oA2 = StP.
If an oAi set as step without any previous oAi set as cPr the configuration alarm “CStP” will be
activated.
StP: valve outputs polarity: polarity of the outputs for capacity valves. It determines the state of the
relays associated with the capacity valves (only for homogeneous and stepped-capacity
compressors):
oP=valve enabled with open contact;
cL= valve enabled with closed contact.
FtyP: Freon Type: set the kind of freon used in the plant
r22 = R22; r404= R404A ; 507= R507; 134=134; r717=r717 (ammonia)
rTy: Type of regulation (see par.15): db = neutral zone, Pb = proportional band.
Sty Activation: type of sequence
YES = rotation: this algorithm distributes the working time between the various loads to ensure even run
times.
no = fixed sequence: the compressors are enabled and disabled in fixed sequence: first, second etc.
12.1.1 Probe 1 configuration
Pbc: Probe 1 setting. Cur = 4 ÷ 20 mA probe; ntc = NTC probe, Ptc = NTC probe.
PA04: Adjustment of read out for the Probe 1 (used only if Pbc=Cur). corresponding to 4mA input
signal, given by the suction probe (0 ÷31 bar or 0÷450 PSI or 0÷3100KPA)
Warning: set a value correspondent to absolute pressure. If the transducer measures relative
pressure increase the range of 1 bar.
See also par. 3.2 How to set the range of the pressure probes
Ex. PP11 relative pressure transducer, range -0.5÷12.0 bar. PA04=0.5 (-0.5+1); PA20=12.0
(11+1).
PP30 relative pressure transducer, range: 0÷30bar. PA04=1; PA20=31.
PA20: Adjustment of read out for the Probe 1 corresponding to 20mA input signal, given by the suction
probe (0 ÷ 31.0 bar or 0÷450 PSI or 0÷3100KPA)) SEE THE WARNING FOR PA04.
CAL: Probe 1 calibration (-12.0÷12.0 bar; -12.0÷12.0°C or -20÷20 PSI/°F)
FcAL: Probe 2 calibration (-12.0÷12.0 bar; -12.0÷12.0°C or -20÷20 PSI/°F)
12.2 OTHERS INPUTS CONFIGURATION
SEP: Polarity of Low pressure-switch alarm (terminals 9-10)
oP =alarm with open contacts; cL= alarm with closed contact
HPP: Polarity of High pressure-switch alarm (terminals HP)
oP = alarm with open contacts; cL= alarm with closed contact
i1c Configurable digital input polarity (terminals 3-4):
oP: the digital input is activated by opening the contact;
CL: the digital input is activated by closing the contact.
i1F Configurable digital input polarity functions (terminals 3 - 4)