Guardian SCC 40 User manual

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
GUARDIAN
SCC
40/35/30/25
Screw Compressor Controllers
•Compressor status monitor with pressure, temperature, slide and load
displays
•Control by suction pressure setpoint or remote 5th pressure
•Control by suction equivalent temperature setpoint or remote 5th
temperature
•Alarm and trip monitoring
•Compressor, pump, slide and speed control
•Economiser, heater and liquid injection control
•Optional Automatic volumetric slide control
•Multiple compressor system control
•Local panel operation and set-up
•Communications for remote monitoring and set-up
•Auto VI Control
Operation and Set-up Manual
GUARDIAN SCC-40/35/30/25 Screw Compressor Controllers provide suction pressure
setpoint control and alarm monitoring for one screw compressor. Alternatively the unit may
be set-up to control on water chiller, glycol chiller or equivalent temperature.
GUARDIAN
Tel. [phone]
Fax. [phone]
Email: [email protected]
www.Guardian-controls.com

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
Contents
GUARDIAN ............................................................................................... 1
SCC........................................................................................................... 1
40/35/30/25................................................................................................ 1
GETTING STARTED................................................................................. 4
BUTTON OPERATION SHORTHAND...............................................................................5
HARDWARE CONFIGURATION CHECKS .......................................................................5
CONFIGURE UNIT MODEL, SYSTEM No & ADDRESS...................................................6
Enter Passcode..............................................................................................................6
Select Unit Model............................................................................................................6
Select System No and Address ......................................................................................7
RS485 Communications.................................................................................................7
UNIT MODELS.......................................................................................... 8
OVERVIEW........................................................................................................................8
Functions........................................................................................................................8
Displays..........................................................................................................................9
Pushbuttons....................................................................................................................9
GENERAL SPECIFICATION...........................................................................................11
Consultant Format .........................................................................................................12
AVAILABLE UNIT MODELS ...........................................................................................13
SCC-40 Input/Output Signals.......................................................................................14
SCC-40 Termination Wiring -........................................................................................15
SCC-35 Input/Output Signals.......................................................................................16
SCC-35 Termination Wiring -........................................................................................17
SCC-30 Input/Output Signals........................................................................................18
SCC-30 Termination Wiring -........................................................................................19
SCC-25 Input/Output Signals........................................................................................20
SCC-25 Termination Wiring..........................................................................................21
OPERATION ........................................................................................... 22
SCC40 PANEL LAYOUT.................................................................................................22
LED LAMPS. ................................................................................................................23
SYSTEM STATUS DISPLAYS......................................................................................24
SAFETY TRIP INDICATIONS.......................................................................................27
DISPLAY PUSHBUTTON OPERATION .......................................................................28
‘view’.............................................................................................................................28
‘type’.............................................................................................................................28
CONTROL PUSHBUTTON OPERATION........................................................................31
“mode”..........................................................................................................................31
“Mode-MANUAL”..........................................................................................................31
“Mode-AUTOMATIC”....................................................................................................31
“RESET”.......................................................................................................................31
“Call Frig Engineer”.......................................................................................................32
“stop”............................................................................................................................32
“start”............................................................................................................................32
“Lower”.........................................................................................................................32
“Raise”..........................................................................................................................32
SETTINGS CHANGE PUSHBUTTON OPERATION........................................................33
“next”............................................................................................................................33
“Accept”........................................................................................................................33
“raise”...........................................................................................................................33

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
“Lower”.........................................................................................................................33
“RESET”.......................................................................................................................33
ALARM ACCEPT AND RESET PUSHBUTTON OPERATION........................................34
SETPOINTS.....................................................................................................................36
CONTROL MODES .........................................................................................................38
CONTROL............................................................................................... 39
COMPRESSOR CONTROL OPERATION.......................................................................39
POWER UP..................................................................................................................39
READY/WAITING.........................................................................................................39
STARTING ...................................................................................................................40
RUNNING.....................................................................................................................41
STOPPING...................................................................................................................42
MODES CHANGES......................................................................................................43
TWO SPEED MOTOR CONTROL...................................................................................44
MANUAL MODE 2-SPEED...........................................................................................44
VARIABLE SPEED MOTOR CONTROL.........................................................................44
TWO COMPRESSOR-SINGLE MOTOR OPERATION....................................................47
AUTOMATIC STANDBY COMPRESSOR CHANGEOVER AFTER TRIP.......................50
NOTES ON SET-UP OF AUTO VI FOR HOWDEN COMPRESSOR.... 51
Auto VI Operation:..........................................................................................................51
Procedure.......................................................................................................................52
Auto VI Commissioning Parameters.............................................................................53
Auto VI Drawing............................................................................................................55
Auto VI Wallbox Wiring.................................................................................................56
TIMER SETPOINTS.........................................................................................................57
SETUP..................................................................................................... 59
Compressor Settings.....................................................................................................59
Unit Settings:................................................................................................................59
System Settings............................................................................................................60
Port Settings.................................................................................................................61
Analog..........................................................................................................................61
Test ..............................................................................................................................62
Done.............................................................................................................................62
TWO SPEED MOTOR CONTROL SELECTION...........................................................63
TRANSDUCER SETUP & CALIBRATION...................................................................64
COMMUNICATIONS............................................................................... 67
MAIN SET-UP/ COMMISSIONING PARAMETERS .............................. 68
Setup / Commissioning Parameters .............................................................................71
PRESSURES ...............................................................................................................71
TEMPERATURES........................................................................................................72
EQUIVALENTS ............................................................................................................72
DIFFERENTIALS..........................................................................................................73
TIMERS........................................................................................................................74
Settings display and change facilities..........................................................................75
SCC-40 Enclosure wiring: for trips negative................................................................77
SCC-40 Enclosure wiring: for trips positive.................................................................78
Local Communications..................................................................................................79
Standard Wallbox Internal wiring ..................................................................................80
Standard SCC 40 Drawing............................................................................................81
FITTING NEW EPROM........................................................................... 82
Index................................................................................................................................83

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
GETTING STARTED
Guardian Controllers provide refrigeration engineers with
•ULTIMATE FLEXIBILITY
•ASSURED MONITORING
•RELIABLE ALARMS
This manual provides refrigeration designers, installers, service mechanics and supermarket
personnel with the necessary information to achieve the above objectives.
All users require to know a few basic facts about this controller before successfully starting to
perform their design, commissioning, maintenance or operating functions.
a) All GUARDIAN controllers need to be set up with a unit model selection and other basic
settings for setpoints, timers and addresses.
b) The shorthand used in the following chapters for concisely expressing button pressing and
selection sequences to do all this set-up needs to be understood.
c) Mains power input voltage and hardware switch and link option selections (if any are
required) must correspond to the selected unit model configuration.
d) Since each controller can be configured in a number of different ways to perform flexible
refrigeration control then an understanding of how to find out what unit model is currently
selected, what it does and how it is connected, is also necessary.

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
BUTTON OPERATION SHORTHAND
To assist in easy set-up of control setpoints, delays, timers and other configuration settings,
the sequence of button presses and subsequent displays will be shown in this handbook as
below:
ii) A button symbol, followed by text means press that button. “@accept”
iii) A double button, followed by text means press that button repeatedly. “@:@raise”
iv) A display box with the window above it shows the result of the last button press on
the display.
DISCHARGE FILTER
==== 2.0b “@:@raise”
DISCHARGE FILTER
==== 2.5b
v) DISCHARGE FILTER DISCHARGE FILTER
H.P. ==== trip ====
Means the display alternately flashes between identifier and trip message
HARDWARE CONFIGURATION CHECKS
Prior to switching on the GUARDIAN controller check that the hardware unit is the correct
type for the incoming mains voltage.
When satisfied that the correct type of controller is available then the following checks should
be made prior to controller installation or replacement
a) Ensure mains supply is wired correctly to the appropriate TERMINAL WIRING drawing for
the model selected.
b) Ensure that any transducer selector switches specified on the TERMINAL WIRING
diagram are in the correct state.
c) Ensure any shorting link selector pins specified on the TERMINAL WIRING diagram are
correctly fitted.
d) Ensure that probes are wired to the terminal WIRING DIAGRAM and the correct type of
thermistor or pressure transducer probes are fitted.
e) The RS485 highway connections (if required) are wired to the correct terminals and the
screen drain wire is continuous to earth.

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
CONFIGURE UNIT MODEL, SYSTEM No & ADDRESS
Enter Passcode
Before any permanent change of controller settings are made then the correct entry of the
appropriate passcode is necessary.
The settings available for change on each passcode are as follows; Passcode
Passcode level 1 setpoints, low & high alarm settings 07
Passcode level 2 low & high trip settings and all level 1 09
Passcode level 3 system settings and levels 1 & 2 15
Enter passcode 15
DISCHARGE FILTER “@view”= “SETPOINT” “@next” “@next”
pASS codE
DISCHARGE FILTER DISCHARGE FILTER
==-= ==12 “@:@raise”==-= ==15 “@accept”
Press “view” to select “SETPOINT”, then press the “next” button twice to enter
the passcode settings.
Press “raise” repeatedly until passcode 15 is selected and then press “accept”
Select Unit Model
Enter Passcode as button sequence above.
“@:@view”= “SYSTEM”
SUCTION OIL “@:@type”= “SAFETY TRIPS”
==sE tUP=
DISCHARGE FILTER
==== =yEs “@accept”
DISCHARGE FILTER DISCHARGE FILTER
==== Unit “@accept”==== SC30 “@:@raise”
DISCHARGE FILTER
==== SC40 “@accept”
Press ‘view’ repeatedly until ‘SYSTEM’ is selected.
Press ‘type’ repeatedly until ‘SAFETY TRIPS’ is selected. Press ‘accept’
‘Unit’ is displayed press ‘accept’
Display shows unit model currently selected which may be wrong.
Press ‘raise’ repeatedly until correct model is displayed (e.g.SC30) and then press ‘accept’
which causes the display to wink briefly and display the new unit model selection
(e.g SC40 )

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
Select System No and Address
e.g. setup unit for system 65 compressor number 1 at address 195
Enter setup as button sequence as above
SUCTION OIL
==sE tUP=
DISCHARGE FILTER
==== =yEs “@accept”
DISCHARGE FILTER DISCHARGE FILTER
==== Unit “@accept”==== sC40 “@next”
DISCHARGE FILTER DISCHARGE FILTER
==== Sn01 “@:@raise”==== Sn65 “@accept”
DISCHARGE FILTER “@next”
==== Cn01 “@accept”
DISCHARGE FILTER “@next”
==== A=01 “@:@raise”
DISCHARGE FILTER
==== A195 “@accept” “@:@next”
DISCHARGE FILTER
==== donE “@accept”
RS485 Communications
When the correct system number, case/compressor number and highway address have been
entered as above then the controller can communicate with the GUARDIAN Consultant
Terminal PC for central alarm monitoring and temperature display. Control setpoints, defrost
times and alarm limits may then be sent to the controller from the PC.
For further details see page 63

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
UNIT MODELS
Guardian controllers may be configured in a number of different ways dependent on unit
model selection. Each unit model fulfils a different refrigeration temperature monitoring and
control requirement. In order to perform the required refrigeration control then each model
has different uses for the controller’s input output signals. This section gives details of all the
model variations available for the controller and the way to connect the wiring to the plant
devices and measuring transducers.
OVERVIEW
Functions
The GUARDIAN SCC-40 controller provides facilities for:-
MONITORING
Measurement of pressures, temperatures, load and slide inputs for control, alarm and
trip display
Calculation of differential pressures and superheat temperatures for control, alarm and trip
display.
Detection of digital input states or safety trip inputs.
ALARMS
Detection after a preset guardtime of pressure and temperature High/Low alarms when the
compressor is in operation. Alarms are indicated by alternating a =Hi= or =Lo=
message on the appropriate temperature or pressure display.
TRIPS
Detection of pressure and temperature High/Low trips which stop the compressor. Trips are
indicated by the flashing red TRIPPED lamp and an alternating 'TRIP' message on the
appropriate temperature/pressure display.
All measurement values are frozen after detection of a trip condition. This facility provides
information on the compressor state, pressures and temperatures when the trip occurred
until after the RESET pushbutton has been pressed.
Detection of safety trips which stop the compressor.
Trips are indicated by the flashing red TRIPPED lamp and an appropriate message.
Trips vary dependent on pack model configuration.
ie :- L.P. ,H.P. ,LEU=,fLo= alternating with a trIP message on the
appropriate display.
CONTROLS
Oil pump, motor and economiser startup and run sequences using preset timers and limits
Compressor status is indicated by LED lamps on the control panel.
Compressor capacity slide valve raise / lower control dependent on suction pressure or
slide control setpoint. The slide valve is automatically lowered when over-current limit or high
discharge pressure are detected or the compressor is stopped.
Suction pressure or slide control initiation of other compressors in the system via a RS485
link when in REMOTE mode.
Oil heater and liquid injection control on oil sump and discharge temperatures.
Various vi type control outputs including VI control, condenser FAN control, extra injection
and standby compressor.

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
Displays
i). SUCTION, DISCHARGE, OIL & FILTER.
SUCTION OIL
2.1b 11.7b 4-digit 7-segment LED displays for display of
measurements setpoints/limits for temperatures and
pressures
DISCHARGE FILTER The contents change dependent on ‘view’ and
10.2b 11.5b ‘type’ selections
ii). CAPACITY%.
CAPACITY%
100 3-digit 7-segment LED displays for display of loading timers
and capacity.
iii). MOTOR LOADING%.
MOTOR LOAD%
105 3-digit 7-segment LED displays for display of timers and
motor load.
iv). COMPRESSOR No.
No
11-digit 7-segment LED display
Pushbuttons.
All pushbuttons are embossed, tactile membrane switches.
start, stop, raise & lower used to control compressors when in manual mode.
RESET used after a trip to reset the compressor.
Mode, view & type used in conjunction with appropriate LED displays to select
control, display or settings change facilities.
accept, next used in conjunction with raise, lower and appropriate LED
displays during setpoint and limit settings changes.
Unaccepted alarms and trips are acknowledged by pressing accept.
Pushbuttons on the local control panel permit operator display of setpoints, pressures,
temperatures, alarm and trip settings and compressor runhours and status.
Setpoints, alarm and trip settings may be changed from the panel after entry of the
appropriate passcode.

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GUARDIAN SCC-40 Issue (Auto VI) & V3.6t 07/12/00
The compressor may be selected to operate in one of three control modes:-
MANUAL, LOCAL or REMOTE MODES.
Safety interlocks, alarm, trip, startup and shutdown sequence controls are automatic in
all three modes.
In MANUAL mode, the each compressor may be individually started and stopped and the
pack capacity raised and lowered by operator pushbutton control from the local panel.
In LOCAL automatic mode, the compressor is started and stopped under control of the
suction pressure setpoint.
REMOTE automatic mode allows up to six RCC-40 units to be connected via a two-wire
communication link (RS485) to provide 6-unit system control.