• 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
• 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
• 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
• 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
• In case of applications in industrial environments, the use of mains filters (our mod. FT1) in parallel with
SAFETY PRECAUTIONS
temperature changes with high atmospheric humidity to prevent formation of condensation
address) with a detailed description of the fault.
other, without crossing or intertwining.
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.
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:
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.
Operating instructions
4. User Interface
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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
Alarm menu: By holding it pressed for 3s, the current alarm is erased.
oooo
In programming mode: it browses the parameter codes or increases the displayed value. With Hot key inserted: it starts the Hot key programming procedure.
operation.
(UP) To enter the Alarm menu.
nnnn (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
e
e
ee
By holding it pressed for 3s the Maintaining menu is entered.
Flashing Load 1 is waiting to start (1HZ). or digital input alarm for Load 1 (2Hz).
ON Load 2 on
Flashing Load 2 is waiting to start (1HZ). or digital input alarm for Load 2 (2Hz).
ON Load 3 on
Flashing Load 3 is waiting to start (1HZ). or digital input alarm for Load 3 (2Hz).
ON Load 4 on
Flashing Load 4 is waiting to start (1HZ). or digital input alarm for Load 4 (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
o Load 1 in maintenance status (2Hz).
o Load 2 in maintenance status (2Hz).
o Load 3 in maintenance status (2Hz).
o Load 4 in maintenance status (2Hz).
5. How to see and modify the set point
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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
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 To exit: push the SET key or wait for 30 without pressing any keys.
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).
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 oooo or nnnn to 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” + nnnn. When
a parameter is present also in “Pr1” decimal point of the lower display is on.
SECURITY CODE is 321
6.3 HOW TO CHANGE PARAMETER VALUES
1. Enter the Programming mode.
2. Select the required parameter with oooo or nnnn.
3. Press the “SET” key the value start blinking.
4. Use oooo or nnnn to 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.
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.