JTL USER GUIDE COMPRESSOR PACK
Contents
1. N x Zz a a O O N N a KS N VS 3 8 N S 121110 9 3 SUCTION PRESSURE CONTROL DISPLAY MU 7 IP5 A v ELN 141 Jnet Zone seral PORT 15 16 17 18 19 20 21 22 23 24 25 26 27 28 VVQVYVOYOVVOVOVOY WY w PRESSURE TEMPERATURE SENSORS TRANSDUCERS 5K THERMISTOR 4 20mA r Jnet Zone PLANT ZONE Doc 04289 ISS 1 The controller can be checked and the operation adjusted using a JTL portable maintenance unit which plugs into the controller Each item of information has an item number The more important items are listed in the tables overleaf Example To read a 21 press To set item 41 to amp 0 press 2 OOe20000e To correct errors press To select next or previous items press hra E Initial Commissioning and Bitswitch Settings The controller has 3 sets of data built in to its program for use during commissioning These can be accessed by setting the virtual bitswitches as shown in the table overleaf The virtual bitswitches are set using item 966 Then set item 9 to 1234 This loads into the controller a suitable set of data for the selected type of case Adjustments should then be made as necessary The range over which the settings can be adjusted is also defined by the bitswitch setting If a JTL communications network is connected to the controller then the unit number should be set on item 1 Pressure Display The pressure2. can be displayed in psi bar or kPa as selected by item 179 The LP210 amp LP220 controller drives the JTL LCD14 display using a CAB75 cable Various cable lengths are available Suction Pressure Control Strategy The compressor capacity is controlled by measuring the suction gas pressure item21 and attempting to maintain this at a constant set value within certain constraints The suction pressure of the compressor pack is controlled by varying the number of steps of compression The controllers can control an inverter trim compressor When the inverter trim control is available the inverter varies the compressor speed on the trim machine to maintain the pressure Only when the inverter driven compressor is running at minimum or maximum speed will the other compressors be stopped or started as required JTL USER GUIDE When a change in compressor capacity is required the controller decides which step of capacity is to be changed The decision is based on the following The maximum number of starts per hour on an individual compressor The compressor running hours are balanced All machines are run periodically Unnecessary starts and stops of the compressors are avoided Capacity of compressors when unequal The suction pressure is maintained within the deadband if sufficient capacity is available The deadband is positioned symmetrically about the suction pressure setpoint so that for example if the setpoint i
3. JTL USER GUIDE Electrical Installation Requirements Care should be taken to separate the power and signal cables to prevent electrical interference and possible damage due to inadvertent connection The power outputs are fitted with suppressors to protect against electrical interference when switching off solenoid valves or contactors It is therefore essential to observe the output polarity The line voltage should be connected to the terminals marked LN and the switched loads to LD The plant inputs are electrically isolated Volt free contacts should be connected for the logical conditions stated below Note inputs 2 to 5 use a common input 14 Terminals 12 11 amp 8 must be linked The control supply neutral must be connected to terminal 1 for EMC operation CE Conformance This unit conforms with the relevant EU standards when installed according to the JTL Installation Requirements for this product Digital Output q 2 LD1 Suppressed High Suction Pressure Alarm 3 LN1 2 4 LD2 Suppressed Watchdog 5 LN2 Digital Inputs g olt F Low Oil Level LP220 only Analogue INPUT Pressure 18 4 20 MA Suction Pressure 17 15 Analogue INPUT Temperature eerie Suction Gas Temperature ta i 2 13 7 4 k k k 5k Thermistor Plant Room Temperature Use of Maintenance Unit COMPRESSOR PACK SUCTION CONTROLLER TYPE LP210 220 SUPPLY A wo ELN VUV 4 LD2
4. ad Compressor 150 unload Compressors 1 amp 2 50 unload Compressors 1 to 3 50 unload When compressor 1 is not set for inverter control all compressors can be used for stage control Capacity Increase When the suction pressure goes above the control deadband the controller will decide when and how an increase in capacity will occur If capacity is available and the pressure does not return within the deadband a change in capacity will eventually occur However the capacity change does not occur immediately the pressure goes outside the deadband There is a minimum delay between each increase in capacity regardless of demand The size and duration of the difference or error between the desired pressure and the actual pressure is taken into account This error is integrated with respect to time When the integrated error is large enough a capacity increase will occur To put this more simply if the pressure error is large a capacity change will occur more quickly than if the error is small Capacity Increase Response Time The speed of response of the system can be adjusted using the increase time constant item 44 The larger the time constant the COMPRESSOR PACK SUCTION CONTROLLER TYPE LP210 220 longer the time before a capacity increase occurs Capacity Decrease When the suction pressure goes below the control deadband the controller program will decide when and how a decrease in capacity will occur If the pr
5. ay Output Rating 2A resistive Supply Requirements 230 V ac 48 62 Hz Supply 6 VA maximum inputs 2 MA maximum 24 Vac optional This unit conforms with the relevant EU standards when fitted in accordance with its installation instructions PREDICT is the patented JTL pattern recognition algorithm for providing defrost on demand for the cabinets on a system Applicable Documentation tem Numbers Firmware Variations Connections Diagram Doc No 03731 Doc No 03732 LP210 Doc No 03713 Installation Information Connections Diagram Doc No 04257 LP220 Doc No 03979 Output Configeration Doc No 03867 Note The information contained in this document applies to the current version of the unit supplied with it Full operating manuals item number and software variation information can be obtained from the supplier JTL Systems LP110 wpd Issue 1 Feb 2014 Doc No 04288 w jtl co uk www j JTL Systems Ltd 41 Kingfisher Court Hambridge Road Newbury Berks RG14 5SJ Tel 10165 263646 Fax 01635 263647 TL Help Desk Tel 08713157535
6. ced off by the maintenance unit items 218 228 up to 308 for compressors 1 to 10 respectively Resulting loading and unloading of the steps of the forced compressor s follows all the normal rules specified above except that the controller ignores the suction pressure on the forced compressor s Forced functions remain in operation for 30 minutes after the MU is unplugged after which time the controller will reset to normal control ALARMS Compressor Faults The individual compressors are continuously monitored The state of these inputs for compressor 1 is shown on item 213 of the maintenance unit Compressor 2 is on item 223 up to compressor 10 which is shown on item 503 The state is indicated by the following messages rdy O ready to run no faults not ready fault f any compressor is not ready to run then this is indicated as a compressor fault item 97 Pressure Alarms The compressor suction pressure is constantly monitored and compared with the high alarm level item 42 If the current suction pressure goes outside the set range for a short time period then an alarm is given The time delay is achieved by integrating the difference between the alarm level and the actual pressure over a period of 30 seconds This means that the larger the difference the faster the alarm occurs Pressure Transducer Alarm The pressure transducer is constantly checked and if after a 15 minute time delay the output goe
7. essure does not return within the deadband a change in capacity will eventually occur As for the increase in capacity there is a minimum delay between each decrease in capacity and the pressure error is integrated with respect to time When the integrated error is large enough a capacity decrease will occur Capacity Decrease Response Time The speed of response of the system can be adjusted using the decrease time constant item 45 The larger the time constant the longer the time before a capacity decrease occurs The use of separate increase and decrease time constants allows the compressors to unload faster than loading if desired This feature is of particular benefit on low temperature stages to prevent the suction pressure going too low Change Of Pressure The change of pressure is also considered If the pressure is going towards the setpoint fast enough for the suction pressure to reach the deadband in an acceptable time then no capacity change is made Starts Per hour Each compressor can be programmed to have a maximum number of starts per hour The item numbers for this selection are 219 for compressor 1 229 for compressor 2 up to 309 for compressor 10 Once acompressor has started it is not allowed to restart again until the restart timer which ensures the starts per hour are observed has timed out Compressor Capacity Each compressor can be programmed to have a capacity The items for this data are 216 for compress
8. it number Daylight saving operation reno Range Units O to 60 100 to 200 0 Disabled 1 Enabled 8 to 60 100 to 150 0 Disabled 1 Enabled 5 to 40 50 to 150 0 Disabled 1 Enabled 10 to 80 200 to 300 0 nor in use 1 in use O not stage controlled 1 stage controlled 2 2 stages 50 100 compressor 1 3 only 3 2 stages 66 100 compressors 1 3 only ae control compressor 1 only 1 psi 2 bar 3 kPa 0 1 899 7 f i O standard time 1 daylight saving time 1 1200 2 2400 3 4800 4 9600 5 1920 Interface communications speed PLANT INTERFACE Q Frozen Food HFC 1 Chilled HFC 2 Frozen Food CO oy f Where 0 2 is the virtual bitswitch setting on item 966 Bitswitch Selection a6 TE gt wn SE gt m JTL USER GUIDE COMPRESSOR PACK SUCTION CONTROLLER TYPE LP210 220 PRESSURE COMPRESSOR R DATA WHERE x IS INVERTER Pressure COMPRESSOR Average p pressure 4hr Status Current proportional term current integral term CONTR Run hours 10 s of hours Steps running Optimised LT setpoint Run time last 24 hours Run hours 10s of hours Optimised HT setpoint Restart timer inverter compressor status Integrated pressure error Starts per hour last 24 hours Next increase site kw Next ee step kw Capacity loaded PACK D Note compressor 10 uses items No of della on load 300 309 360 380 No of compressors running Loaded capacity kw Rel
9. or 1 226 for compressor 2 up to 306 for compressor 10 The capacity control takes account of the capacity that can be started and stopped to ensure optimum control Where a small capacity change can be made by starting and stopping two machines to give a net change in capacity this is done In this condition the machine to be started always starts before the machine to be stopped regardless of whether capacity is to be increased or decreased High Discharge Pressure If the discharge pressure exceeds the pressure safety level on input 2 then the compressor capacity is reduced There is a choice of two actions in this condition on item 197 either the reduction in capacity is controlled by the normal sequence of unloading or all conpressors are stopped immediately When the pressure falls below the safety level the capacity is allowed to increase again according to the normal requirements of the suction pressure Low load Condition When the refrigeration load is low enough for the compressors to run on 1 step only including the trim compressor then to prevent the last compressor stopping unnecessarily the deadband lower limit is automatically lowered reducing the pressure at which the last compressor would be stopped In this condition the deadband lower limit is set to the 1st stage hold on pressure setpoint item 48 There is a very low suction pressure setting item 196 below which if enabled by item 195 will stop all comp
10. ressors instantly INVERTER CONTROL Inverter Speed Control The inverter requires the use of an analogue interface module IF35 which can vary the frequency of the inverter drive is varied using a 0 10 signal The inverter should be set up so that O V is for minimum speed and 10 V is maximum speed Capacity Control The controller starts and stops the inverter as required taking account of any other compressors controlled by the same suction pressure The inverter automatically acts as a trim compressor and all the normal compressor capacity control functions are operational The capacity of the compressor at minimum and maximum speed is programmed on items 335 and 336 Minimum Speed When there are no other compressors running the inverter will stay on at minimum speed until the minimum pressure set on item 341 is achieved Control Response The controller uses proportional and integrated control algorithms to control the inverter These require speed gain item 339 and time constant item 340 to adjust the response of the control of inverter Speed Output Limits The speed output can be limited at both maximum and minimum speed The settings for the limits are item 342 for maximum and item 343 for minimum speed MAINTENANCE FACILITY Forcing a Compressor to Run A particular compressor may be forced to run by the maintenance unit MU items 217 227 up to 307 for compressors 1 to 10 respectively Any compressor may be for
11. rk controller then adjusts the times automatically during the daylight saving period JTL USER GUIDE O i k 5 Suction pressure maximum 5 to 60 175 to 225 5 Deadband 0 to 20 S ncrease time constant 1 to 60 Decrease time constant 1 to 60 D COMMON COMPRESSORS WHERE COMPRESSOR PRESSURE X IS COMPRESSOR COMPRESSO NCTION R ALARMS JNET FU COMPRESSOR PACK SUCTION CONTROLLER TYPE LP210 220 ADJUSTABLE PARAMETERS Function Suction pressure setpoint minimum Suction optimisation 1 stage and fast unload set point Low suction pressure safety Low suction pressure safety level nstant high discharge pressure shutdown High suction pressure a P 2 Low suction pressure 5 to 40 100 to 150 w aw oO Transducer O Disabled 1 Enabled a Transducer full scale at 20mA 50 to 200 300 to 500 E Transducer zero scale at 4mA 145 to 0 Number of compressors 41 to 10 Maximum allowed to run 1 to 10 Minimum stop time 0 to 240 Isolation Capacity Control Starts per hours ote compressor 10 uses items 300 309 Display units Select 0 Disabled 1 Enabled Ainimum pressure 8 to 40 100 to 150 th Time constant 1 240 amp Gain 1 250 inimum steps 1 63 z aximum steps 64 127 Capacity at minimum speed 1 100 Capacity at maximum speed 1 100 5 a 206 Fault alarm delay 0 10 158 Fault alarm repeat delay 00 01 24 00 00 00 off 175 Low refrigerant alarm delay 15 240 Un
12. s outside the acceptable range an alarm is given item 91 If there is a suction pressure transducer fault the number of compression steps is set to the maximum available Control then reverts to the compressor LP safety switches All normal sequencing restart delays etc will be maintained in this mode of operation Low Liquid Level LP220 only An input is available to monitor low liquid level in the receiver The input should be shorted out when there is no alarm condition An alarm is given after an adjustable delay item 175 the contact is opened Low Oil Level LP220 only An input is available to monitor low oil level in the system The input should be shortened only when there is no alarm condition The alarm iS given 10 seconds after the input occurs Alarm Display Various alarms are indicated on the pressure displays Typical messages displayed are P FIC Plant fault auto input not present highest priority Hi Sp High suction pressure Hi dP High discharge pressure Lo Li Low level liquid Cpr Compressor fault lowest priority The alarm conditions are flashed alternately with the pressure In the event of there being more than one alarm the highest priority alarm is displayed DAYLIGHT SAVING NETWORK When connected to a JTL network this controller can operate by displaying daylight saving time for its time and defrost schedule Daylight saving operation is selected by setting item 18 The connected netwo
13. s set to 8 psi and the deadband is set to 4 psi then the bottom of the deadband is 6 psi and the top 10 psi Under normal conditions when the suction pressure is within the deadband no increase or decrease in staged capacity will occur Suction Pressure Optimisation When used in conjunction with a JTL suction pressure optimiser SPO and appropriate JTL evaporator controllers monitors the suction pressure can be optimised to save energy The optimiser monitors the evaporator conditions and sets the suction pressure to the appropriate level to maintain the evaporator at the optimiser level to achieve the desired temperatures at the lowest energy The allowed range of pressure is set on items 40 minimum and 152 maximum optimisation is enabled on item 150 CAPACITY CHANGES STAGE CONTROL The stage control is implemented using additional digital interface IF modules One or two IF31 modules are used depending on the number of compressors and stages on the compressors Up to 8 stages can be controlled using one IF31 module and up to 14 stages can be controlled using IF31 modules Note when using two IF31 modules stages 1 7 are on IF1 amp 8 14 on IF2 The output arrangement for multistage compressors is controlled using item 167 Compressor output configuration Note When compressor 1 is set for 50 unloader then the inverter is disabled All compressors 1 stage Compressor 2 50 unload Compressors 2 amp 3 50 unlo
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