GEA Grasso User manual

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2003/0 638660_um_gsc_gbr
GRASSO SYSTEM CONTROL
Standard Package with Piston Compressors
Single Stage and Two Stage
Manual

Copyright Grasso GmbH Refrigeration Technology
The contents of this documentation and the enclosed drawings, sketches and diagrams are intended only for plant
users and operating personnel. They may be neither duplicated nor divulged to third parties or firms without
written consent.
The technical data, figures, dimensions and weights presented in the documentation may be more closely defined
or otherwise specified as a result of contractual agreement and are binding only after our confirmation in writing.
The stipulations set forth in the contract have precedence over those in this documentation.
We reserve all rights to introduce technical modifications in the course of further development.

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FOREWORD
DESCRIPTION OF GRASSO SYSTEM CONTROL 1
CONTROL SEQUENCE 2
INITIAL START UP3
SYSTEM DESCRIPTION 4
TECHNICAL DATA 5
ALARMS 6
TROUBLESHOOTING 7
SERVICE 8
APPENDICES 9

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FOREWORD
Introduction
Grasso has been producing refrigerating compressors and compressor units for a wide range of different
applications for several decades.
A new compressor control has been developed for universal use based on our many years’ operational
experience.
The compressor control, type “GSC“ (Grasso System Control) is a highly modern programmable controller, which
is based on the Simatic C7-633 system.
The GSC is suitable for controlling and monitoring our company’s compressors.
Explanation of the abbreviations used
The following abbreviations are used in this manual.
Abbreviation Description
GSC “Grasso System Control“ Type designation of the Grasso standard compressor control
CP “Communication processor“
CPU “Central processing unit“
DP “Decentralised periphery“
Eco “Economizer“
EPROM “Erasable programmable read-only memory“
Ext. “External“
RF „Refrigerant“
RF-separator “Refrigerant separator“
LED “Light-emitting diode“
MAX “Maximum“
MIN “Minimum“
MPI „Multi Point Interface“ Siemens internal, interface with multi-point capability on the GSC,
used for communication between several controls.
MRES „Memory Reset“
SV „Solenoid valve“
LVS “Low Voltage switchgear“ — switchgear with power contactors for compressor motor, oil
pump and oil heating
OP “Operator panel“ control and display device
PG “Programming device“
PLC “Programmable logic controller“
P & ID “Pipe and instrumentation diagram“
General drawings
This drawing shows the general configuration of a piston compressor unit type “Grasso6210“ with economiser.
The supplied model can deviate from this.

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Figure 0.1: View of piston compressor unit, type Grasso6210 with economiser
oil separator
piston compressor
GSC
drive motor
suction side stop valve
coupling
terminal box
economiser
discharge side stop valve

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General P & ID
This diagram is intended to give a general overview of the measuring points provided. The supplied unit may
deviate from this diagram.
MAIN SWITCHGEAR CABINET MAIN SWITCHGEAR CABINET
Input signals Additional output signals
Motor feedback
Motor thermal protection Start motor
Emergency Stop Start oil pump
External ‘ON’ Ready
External ‘LESS’ Running
External ‘MORE’ No alarms
Start release
External reset
Liquid level switch
Gas sensor
Setpoint switch
Figure 0.2: P & ID

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01.2003/0 638660E_chapter1.doc
1DESCRIPTION OF THE GRASSO SYSTEM CONTROL 1
1.1 Grasso System Control - General 1
1.1.1 View 1
1.1.2 Lamps/ Push buttons 2
1.2 Operator terminal 2
1.2.1 Key assignment 3
1.2.2 Menu structure 4
1.2.2.1 Password level 4
1.2.2.2 General image format 5
1.2.3 Call up table of contents 6
1.2.3.1 Actual values menu 6
1.2.3.2 Control settings menu 8
1.2.3.3 Operating mode menu 9
1.2.3.4 Limit values menu 9
1.2.3.5 Alarm menu 13
1.2.3.6 Timer Settings menu 13
1.2.3.7 Unit options menu 14
1.2.3.8 Configuration menu 14
1.2.3.9 System Main Menu 17
1.3 Status display 18

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1DESCRIPTION OF THE GRASSO SYSTEM CONTROL
1.1 Grasso System Control - General
The GSC consists of the control unit with operator keypad and display unit, indicator lights for “Running“,
“Warning“ and “Alarm“, emergency stop button, output relays etc.
The standard GSC is directly mounted on the compressor package unit. However, the GSC can also be located in
a control centre.
The GSC performs the following functions:
-Display of all physical and technical parameters - e.g. pressure, temperature, motor current, capacity, number
of hours run, operating mode and status signals.
-Automatic start up and shut down of the compressor unit and capacity regulation dependent on the
following parameters: - suction pressure
- external temperature (analogue or network input)
- inlet temperature (Chiller only)
- outlet temperature (Chiller only).
-Monitoring of all operating parameters.
-Compressor capacity limitation, in case the discharge pressure, discharge temperature, suction pressure,
secondary refrigerant temperature or motor current limits are approached.
-Alarm memory with date and time.
-Wire failure detection of analogue input signals.
-Password protection for preventing unauthorised access to parameters.
-Program memory on EPROM.
-Control of the compressor unit by a master controller via potential free contacts.
-MPI or Profibus-DP communication with a master controller.
-Freeze display with all operating parameters just before appearance of the last alarm that results in the unit
to shutdown.
1.1.1 View
1Power supply 4Emergency stop relay
2Profibus DP/DP-coppler 5Motor start relay
3Socket-outlet for service 6Bus Terminal
Figure 1.1: View of outside of switchgear cabinet Figure 1.2: View of inside of switchgear cabinet
1
32
6
4
5

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1.1.2 Lamps/ Push buttons
)White indicator light (Running)
This indicator lamp flashes slowly when the compressor unit is in the “Ready“ state.
This lamp flashes quickly during start up of the compressor.
Once the compressor has started, the light becomes steady.
This lamp flashes quickly during the shut down operation, until the compressor drive motor is switched off.
)Yellow indicator light (Warning)
This lamp flashes if an operating condition reaches a preset value (Warning /Pre-alarm).
Detection of this warning can be acknowledged at the operator panel. After the warning has been
acknowledged at the operator panel, this flashing light changes over to a steady light, as long as the warning
condition remains.
When the operating conditions are back to normal the warning is automatically reset and the indicator light
switches off again.
)Red indicator light (Alarm)
This lamp flashes if an operating condition exceeds its permitted value, the machine shuts down on alarm.
This state is signalled by a red flashing light. After the alarm has been acknowledged at the operator panel, this
flashing light changes over to a steady light, as long as the alarm condition remains.
Once the cause of the alarm has been corrected, this indicator light switches off (after it has been
acknowledged).
)Emergency stop button
This red button can be used to switch the compressor unit off at any time in case of an emergency. The operator
terminal controls remain functional.
1.2 Operator terminal
The operator terminal is the interface between the operator and the control unit.
All switching, operating and control actions are carried out via this operator terminal.
System LED’s function keys soft keys CPU operating mode setting
digital keybord cursor keys system keys system keys LED‘s
Figure 1.3: GSC operator terminal
)For detailed explanation of the system LEDs see Chapter 4.1

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1.2.1 Key assignment
Key Function
Change to the next display window
F2, F3 Go to the menu item described in the text display directly above
Switch on the compressor unit, start enabled
Start 1st compressor (Press key for 5 sec. in operation mode “Manual”).
Increase capacity of 1st compressor (In case of manual capacity control only)
Start 2nd compressor (Press key for 5 sec. in operation mode “Manual”).
Increase capacity of 2nd compressor (In case of manual capacity control only)
No function
Call up display of actual values
Call up alarm signals
Lamp test
Switch off the compressor unit, start disabled
Stop 1st compressor (Press key for 5 sec. in operation mode “Manual”).
Reduce capacity of 1st compressor (In case of manual capacity control only)
Stop 2nd compressor (Press key for 5 sec. in operation mode “Manual”).
Reduce capacity of 2nd compressor (In case of manual capacity control only)
No function
Call up controls — settings
Call up operating mode setting
Call up the menu overview
Return or cancel input
Acknowledge, reset failure and warning
Confirm input
Press the button once for display of a help text. In some screens two levels of
help are available by pressing the button twice.
Switch over to the 2nd keyboard level
Cursor keys

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)Functions for F1…F4 keys
These functions are only available if the symbols can be seen in the display.
Back to previous display
Go to the menu item described
Move to next display
)Standard function of the shift keys
+ or Change between the possible selections
+ Alter the display contrast
)Special function of the shift key
+ Change to the “Status display”
+ Change to the “freeze Display“ menu
+ Change to the “Language selection” or “Contrast menu”
+ Change to the “Transfer“ menu. Attention: stop with
+ Change to the “Digital inputs / outputs display“
+ Change to the “Password“ menu
+ Change to the “Date, Time“ menu
1.2.2 Menu structure
1.2.2.1 Password level
The access rights within the menu structure are protected by different passwords.
The operator is asked to enter a password when they try to enter a command.
The password consists of a 4-figure number.
Each password level has a different number allocated to it.
The passwords for Levels 1 to 8 can be freely allocated by the user.
The password for the highest password level 9 is specified by Grasso on delivery and cannot be subsequently
changed.
If a password is entered and then no key is used for a longer period (approx. 10 mins), the operator panel
automatically logs out from the password level.

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)The following password levels have been allocated:
Password level 1Operator level Change to the set point values possible.
Password level 2Only for authorised persons Changes to all limiting values/timers possible —
in addition to Level 1
Password level 8Service level Changes in the configuration menu possible —
in addition to level 2
Password level 9Grasso only Changes in the system menu possible —
in addition to level 8
1.2.2.2 General image format
The image format is identical in all the images.
parameter text 1 
parameter text 2 
parameter text 3 
Menu title 01 >>
Back next
Depending on the menu, the actual or set point values are displayed in the 3 top rows.
The name of the selected menu is displayed again in the lowest row.
The double arrows or mean that you can move to the previous menu display or the next menu
display by pressing the key under this symbol.
If a menu is selected in which further branches are possible, the image format is as follows:
Menu title
Select 1 select 2
<<  >>
back accept accept next
select 1 select 2
The current image name is displayed in the top row.
The keys under the symbols and are used to return to the previous menu display or to the next
menu display , and thus to further possible selections.
The described function is selected using the and keys under the symbols.

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1.2.3 Call up table of contents
To get to the table of contents, press the key. A list of the available menus is then displayed.
Number Title Help text
05 Actual values Display of all unit’s actual values
10 Control settings Display and set up of all control parameters
15 Operating modes Selection of operation mode
20 Limit values Set up of alarm, warning and limitation parameters
25 Alarms Display of current and previous alarms
30 Timer settings Set up of timers
35 Unit Options Selection of unit option menus
50 Configuration Enter: - Refrigerant used
- Compressor type - With/without economiser
- Scaling of the sensors - Number of cylinders
90 Main system menu
To get to these menus, position the cursor on the menu name (using the or key) and confirm with
the key.
)Parameter changes in menu 20, 30, 35, 50 can cause serious damage to the piston compressor unit!
1.2.3.1 Actual values menu
05 Actual values
PV  SP 
Cap  Imot 
Tc  dPoil 
Actual values 01 >>
PV: Process Variable, display in °C/R (pressure) or °C (temp)
SP: Set Point display in °C / °C/R
Cap: Actual capacity step (for the low pressure stage) in %
Imot: Motor current in A
Tc: Discharge pressure in °C/R
dPoil: Differential oil pressure in bar
Capacity ()  Capacity: Actual capacity step for the high and low pressure stage
Suction press 
Discharge press 
in %
Suction press: Suction pressure in bar (a)
<< Actual values 01 >> Discharge press: Discharge pressure in bar (a)
Oil diff press 
Oil press 
Crankc press 
Oil diff press: Oil differential pressure in bar, calculated from the oil
pressure minus crankcase or suction pressure
Oil press: Oil pressure in bar (a)
<< Actual values 01 >> Crankc press: Crankcase pressure in bar (a)

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Suction temp 
Disch temp 
Oil temp 
Suction temp: Suction temperature in °C
Disch temp: Discharge temperature in °C
Oil temp: Oil temperature in °C
<< Actual values 01 >>
Suct dif temp 
Intm dif temp 
ECO inject  %
Suct dif temp: Suction gas overheat in K
Intm dif temp: Intermediate gas overheat in K
ECO inject: Economiser injection in % (two-stage only)
<< Actual values 01 >>
Suct press °C/R 
Intm press °C/R 
Disc press °C/R 
Suct press °C/R: Suction pressure displayed as temperature
Intm press °C/R: Intermediate pressure displayed as temperature
Disc press °C/R: Discharge pressure displayed as temperature
<< Actual values 01 >>
Interm press 
Interm LP temp 
Interm HP temp 
Interm press: Intermediate pressure in bar (a)
Interm LP temp: Intermediate LP temperature in °C (discharge LP stage)
Interm HP temp: Intermediate HP temperature in °C (suction HP stage)
<< Actual values 01 >>
Remote SP 
External temp 
Oil sep temp 
Remote SP: Remote set point in °C
External temp: External temperature in °C
Oil sep temp: Oil separator temperature in °C
<< Actual values 01 >>
Motor current 
Motor speed 
in A
in rpm
<< Actual values 01 >>
Start to start 
Stop to start 
Start to start: Remaining time between two starts of the compressor
drive motor in secs.
Stop to start: Remaining time between stop and next start of the
<< Actual values 01 >> compressor drive motor in secs

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Unloaded start 
Motor feedback 
Auto start dly 
Unloaded start: Remaining time for unloaded start in secs
Motor feedback: Remaining time for motor running feedback signal from
compressor drive motor starter
<< Actual values 01 >> Auto start dly: Remaining time for automatic start delay in secs
Step time 
Limit time 
Run hours 
Step time: Remaining time for next capacity step in secs
Limit time: Remaining time for the capacity limitation in secs
Run hours: Number of operating hours
<< Actual values 01
1.2.3.2 Control settings menu
10 Control settings
Set Point 1 
Set Point 2 
Active SP 
Set Point 1: First Set Point for the controlled parameter °C
Set Point 2: Second Set Point for the controlled parameter °C
Active SP: Active Set Point in °C
<< Control 01 >> The active set point value is displayed. 2 different set point values can be
entered via the display. The switchover takes place due to a potential free
contact or due to MPI/Profibus-DP communication.
Furthermore, an external set point (analogue input or MPI/Profibus-DP
signal) can be activated. This switchover takes place due to the selected
operation mode in the menu “Operating mode” .
Active SP 
Neutral zone 
Prop zone 
Active SP: Active set point in °C
Neutral zone: Neutral zone of the automatic capacity regulation in K
Prop zone: Proportional zone of the automatic capacity regulation in
<< Control 01 >> K
Step times min | max
Cap inc | 
Cap dec | 
Cap inc min: Minimal step time for increasing the capacity in secs
Cap inc max: Maximal step time for increasing the capacity in secs
Cap dec min: Minimal step time for decreasing the capacity in secs
<< Control 01 >> Cap dec max: Maximal step time for decreasing the capacity in secs
Auto start dly 
Pump down 
Stop pressure 
Auto start dly: Time for automatic start delay in secs
Pump down: Selection between “with” or “without” pump down
Stop pressure: If pump down is activated, the compressor does not stop
<< Control 01 >> before the suction pressure reaches this value in bar (a)
Boost press 
Cor P-zone 
Derative fact 
Boost press: Booster pressure in bar (a) .
Cor P-zone: Correction value of the proportional zone in K for
decreasing the capacity (+ towards the set point / - away
<< Control 01 from set point)
Derative fact: Maximum temperature difference in K allowed within 5
seconds otherwise the capacity will be changed
immediately (0 = derative function deactivated)