Elektronikon MKIV System Description _________________________________________________________________________________________________ 1
General description
The Elektronikon MKIV regulator is the heart of most regulation systems used on Atlas Copco stationary compressors. The Elektronikon regulator is an advanced electronic control and monitoring system specifically designed to operate Atlas Copco stationary air compressors. On fixed speed machines the MKIV regulator maintains the compressed air net pressure between the programmed load and unload pressure settings by loading, unloading, starting or stopping the compressor automatically. The regulator uses an advanced control algorithm called DSS, delayed second stop, to minimize the power consumption of the compressor by only running the drive motor when absolutely necessary. This function also minimizes the number of motor starts to insure a long motor service life. On variable speed drive machines, VSDs, the MKIV regulator continuously compares the net pressure to the operator selected programmed setpoint pressure. The MKIV regulator then sends a control signal to the variable speed drive to adjust the compressor speed to either produce more air, if the net pressure is falling, or to produce less air if the net pressure is rising. The regulator also protects the compressor. It continuously monitors critical parameters of the compressor and shuts the unit down in the event of a problem. It acts as an operator interface allowing an operator access to the information monitored by the regulator through an efficiently laid out menu screen. Service parameters are also monitored and an operator is notified when service is required so that maintenance can be scheduled to suit the plant’s production needs. 2
Elektronikon MKIV Hardware
The MKIV is the latest generation of the Elektronikon regulator. The MKIV consists of three basic master module hardware platforms, Elektronikon I, Elektronikon II and Elektronikon III. The configurations of which type regulator is used on which compressor model along with input and output, I/O, details are given in table one at the end of this document. 2.1
Elektronikon MKIV-I
Elektronikon MKIV-I regulator is a very simple regulator used by smaller compressors that don’t have a lot of I/O requirements. It has a symbol based back lit LCD, liquid crystal display, and is intended to be an electronic replacement for simple electropneumatic control. The MKIV-I regulator has one pressure input, discharge pressure, and two temperature inputs, element outlet and LAT for FF units. The MKIV-I regulator has three digital inputs, emergency stop, motor overload and remote start/stop. The MKIV-I regulator has six digital outputs, star contactor, line contactor, delta contactor, load/unload solenoid valve, general shutdown and dryer control. The MKIV-I requires no programming on commissioning a simple process of parameter selection done at the faceplate of the regulator selecting which compressor is being controlled is all that is required. The regulator has no serial communication or expansion capabilities. The basic operational features that are not available with the MKIV-I that are available with the other regulators are no clock based control function, only one pressure set selection is possible and no sequencer control is possible. 2.2
Elektronikon MKIV-II
The Elektronikon MKIV-II regulator has a lot more features than the type I regulator and is intended to be used on larger compressors that have greater I/O and communication requirements. It has a 4x16 character back lit LCD and is alpha numeric. The type II regulator has two hardware sub platforms, the version A and the version B regulators. The basic functionality is the same between the two regulators the only difference is in the number of I/O and the communication ports that are available. The type II and the type I regulators are physically the same size. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ The version A regulator has one pressure input, two temperature inputs, eight digital inputs, nine digital outputs, a CAN port and an expansion port. The version B regulator has two pressure inputs, three temperature inputs, ten digital inputs, nine digital outputs, an RS485 port (for communication between the Elektronikon and the drive on VSD units), a CAN port and an expansion port. The type II regulators have very flexible communication and expansion capabilities that are detailed later on in this document. 2.3
Elektronikon MKIV-III
The Elektronikon MKIV-III regulator, like the type II, has a lot more features than the type I regulator and is intended to be used on larger compressors that have greater I/O and communication requirements. It has a 4x40 character back lit LCD and is alpha numeric. The type III regulator has two hardware sub platforms, the version C and the version D regulators. The basic functionality is the same between the two controllers the only difference is in the number of I/O and the communication ports that are available. The type III is physically larger than the type I and II regulators. The version C regulator has four pressure inputs, eight temperature inputs, ten digital inputs, nine digital outputs, a CAN port and an expansion port. The version D regulator has four pressure inputs, ten temperature inputs, ten digital inputs, nine digital outputs, an RS485 port (for communication between the Elektronikon and the drive on VSD units), a CAN port and an expansion port. The type III regulators have very flexible communication and expansion capabilities that are detailed later on in this document. 2.4
What’s new with the MKIV
The new Elektronikon MKIV is the latest generation in compressor regulation technology from Atlas Copco. As the Elektronikon has evolved over the years each new generation has built on the experience of the previous generation culminating in the features that make up the MKIV regulator. The new MKIV regulator has all of the functionality of the MKIII plus some new features that make it an improved version. The MKIV has the same stringent hardware specifications as the MKIII from an environmental and electrical standpoint. Many of the distinguishing characteristics that differentiate the MKIV from its immediate predecessor the MKIII are outlined below. 2.4.1
Technology
The MKIV platform is based on today’s latest microprocessor technology. The hardware is more robust than the previous versions. For example the terminal connections where the wiring is connected to the MKIV are changed to WAGO “spring type” connections that are an improvement over the version used previously. These new terminal connections are more resistant to becoming “loose” over time, and making connections is a lot easier. The internal operating system software has been changed to a PLC based system that is widely used in the microprocessor industry. The application software is written in a well known and flexible software that is based on the IEC standard IEC 1131. These improvements make programming changes much simpler and should allow the MKIV system to be more flexible to unique applications. This flexibility will allow the MKIV system to take on more responsibility for control and monitoring of not only the air compressor but also other pieces of equipment that one normally finds in a compressor room. The MKIV has more I/O and as a consequence most of the standard machine configurations that use the regulator do not require expansion modules which reduces the number of components required in a MKIV system over the MKIII. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ The liquid crystal display, LCD, that is used as the operator interface has been improved. The previous version used a black screen with green characters. The new display uses a green screen with black characters and the backlighting of the display has been improved. These two features not only improve the viewing angle of the display but make it easier to read in direct sunlight than the previous version. The basic operation of the MKIV is the same as the MKIII, with many additional features, so theoretically the MKIV can be used to replace the MKIII on any compressor with some work to be done locally. The major items to be considered would be the door panel. The physical size of the MKIV is not the same as the MKIII so the cut out in the cubicle door of the MKIII is not suitable to accept the MKIV. Wiring harness. At the very least the terminal plugs would need to be changed so that the wiring harness would be accepted with the MKIV regulator. The sensors and digital I/O are the same for most compressor variants. Decisions for replacement suitability should be made on a case by case basis for the each application being considered. 2.4.2
Features
The MKIV has many new features built in that make it a significant improvement over the previous generations of regulators. All of the regulator types now have digital output auxiliary relays as standard. With the MKIII LRR a relay expansion module would need to be added. With the MKIV family all of the regulator types have at least one auxiliary relay output. Refer to section 2 detailing I/O of each regulator type. The look and feel of the menus screens has been improved with a more logical ordering of the information available to make scrolling for information easier than with the MKIII. For example all screens indicate with an arrow if more information is contained in a section or if only a warning is present then the warning message will blink. Two pressure sets or pressure bands can be programmed called pressure band 1 and pressure band 2. Different loading and unloading set points can be programmed in so that two distinct pressure bands can be used in the process. These two bands can be selected either manually at the faceplate of the regulator or can be programmed to change at a certain time. This feature is not available for the MKIV-I regulator. Control mode selection is down at the display instead of using digital inputs to the master module as was done with the MKIII. Refer to section 4 for more information on the different control modes that are available. A more comprehensive set of expansion modules is available with no expansion module programming required. Refer to section 3.1 for more information on the expansion capability of the MKIV system. A separate communication module is no longer required for local area networking or VSD communication. The MKIV-II and III have versions which include LAN and RS485 ports as standard built right into the module. Programming of the modules has been greatly improved. The programming of the modules is done over the CAN port, see communication section 3.2 for CAN details. Separate language, setting and expansion module files are no longer required only one file per division is required. The Field Download Program, FDP, is available on the LN software market. The necessary file one needs to program a regulator for an application is available on a LN database dedicated for these files. Language and machine specific selection is done with the FDP and programming of the master module over the CAN is all that is required. The Service Diagnostic Package, SDP, remains to be used for the purposes that it was used for in the past such as programming special input functions. The MKIV-I regulator requires no programming at all. A simple process called parameter set selection is done at the faceplate of the regulator at commissioning to select the machine parameters. A help screen has been added so that a local contact can be added to the module that gives the customer the local contact information. By default the Atlas Copco web site address is featured but this can be modified locally. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Service notification has been simplified. Instead of individual service alarms a series of service plans have been developed. Each service plan has a set of service actions that are detailed in the instruction book of the machine. Two general counters are monitored by the MKIV, a running hours counter and a real time counter. When one of the counters equals a multiple of the service interval detailed in the service plan a service warning is generated. The corresponding service plan is displayed, i.e. Service Plan A, B, C etc. Individually monitored components, for example Oil Separator differential pressure, may indicate that service is required prior to the expiration of a service plan time interval. In cases like this an operator will be notified for the need to service the individual component in question prior to the elapse of a service counter. Multiple Compressor Control, MCC. When activated this feature allows one of the compressors in an installation, up to four maximum, to act as a master compressor controller or sequencer. The MCC feature is described in more detail in section 4.3.2. 3
Optional accessories
The MKIV system is very flexible and complete. The standard options that are available to compliment the MKIV system are described in detail below. The accessories described below are not available on the MKIV-I regulator. The MKIV system can handle up to a maximum of eight modules in one system. For example one master module plus up to a maximum of seven expansion or communication modules per compressor. These accessories can be found on the Lotus Notes database under Options and accessories for the Elektronikon MKIV. 3.1
Expansion modules
One of the many new features of the MKIV system is that the expansion modules are now installed on the back plate of the compressor control cubicle and are DIN rail mounted. Most of the expansion modules require only a cable connection that connects it into the Elektronikon system with no power connections required. Two standard prefabricated cables are available and are listed on the options list in LN. 3.1.1
AIE1
The analogue input expansion module number 1, AIE1, has two inputs for the standard Kavlico pressure transducers and two inputs for the standard Jumo PT1000 temperature resistance temperature detectors, RTDs, used on Atlas Copco compressors. This expansion module could be used if additional temperature or pressure points need to be measured. What is required is the installation of the sensor into the compressor package where appropriate. Run a sensor cable from the sensor to the compressor control cubicle. Mount the AIE1 onto the DIN rail of the compressor cubicle back plate, connect the AIE1 into the Elektronikon system using a prefabricated cable listed on the options list. Then finally program the regulator using the FDP or SDP program to accept the input and its intended function. 3.1.2
AIE2
The analogue input expansion module number 2, AIE2, has four inputs for 4-20 mA analogue inputs. This expansion module could be used if additional 4-20 mA inputs need to be measured. What is required is the installation of the sensor into the compressor package where appropriate. Run a sensor cable from the sensor to the compressor control cubicle. Mount the AIE2 onto the DIN rail of the compressor cubicle back plate, connect the AIE2 into the Elektronikon system using a prefabricated cable listed on the options list. Install a separate 24VDC power supply into the cubicle and wire this power supply to the module, we recommend ps 1089045773 which is an Omron S82K-00324 100-240VAC to 24 VDC, 3 W. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Then finally program the regulator using the FDP or SDP program to accept the input and its intended function. 3.1.3
AIE3
The analogue input expansion module number 3, AIE3, has five inputs for PT 100 temperature RTDs. This expansion module could be used if additional temperature points are needed and the RTD is a PT 100 style. What is required is the installation of the sensor into the compressor package where appropriate. Run a sensor cable from the sensor to the compressor control cubicle. Mount the AIE3 onto the DIN rail of the compressor cubicle back plate, connect the AIE3 into the Elektronikon system using a prefabricated cable listed on the options list. Then finally program the regulator using the FDP or SDP program to accept the input and its intended function. 3.1.4
AIE4
The analogue input expansion module number 4, AIE4, has five inputs for PT1000 temperature RTDs. This expansion module could be used if additional temperature points are needed and the RTD is a PT1000 style. What is required is the installation of the sensor into the compressor package where appropriate. Run a sensor cable from the sensor to the compressor control cubicle. Mount the AIE4 onto the DIN rail of the compressor cubicle back plate, connect the AIE4 into the Elektronikon system using a prefabricated cable listed on the options list. Then finally program the regulator using the FDP or SDP program to accept the input and its intended function. 3.1.5
DIOE
The digital input/output expansion module, DIOE, allows the addition of up to two digital I/O to be incorporated into the MKIV system. This expansion module would be used if a user wanted to add extra digital inputs to a compressor. For example if a customer wanted to indicate a high filter differential pressure on a set of pre-filters that were added to the compressor in the field. One would connect the auxiliary contact from the dp switch to the DIOE input. What is required is the installation of the sensor into the compressor package where appropriate. Wire the contacts, they must be voltage free, from the indicator to the control cubicle. Mount the DIOE onto the DIN rail of the compressor cubicle back plate, connect the DIOE into the Elektronikon system using a prefabricated cable listed on the options list. Then finally program the regulator using the FDP or SDP program to accept the input and its intended function. 3.2 Communication modules A series of communication modules have been developed that allow the MKIV system to be connected to a users plant wide communication network. These modules, ComBox-yy, convert the CAN protocol used by the Elektronikon into the communication protocol used by the installation. The Elektronikon MKIV regulators, not MKIV-I, all have a field bus port built in as standard. The fieldbus used by the MKIV is called CAN. CAN, Controller Area Network, is an ISO approved standard communication protocol that was developed in 1984 by Bosch for in vehicle data transmission. It is a very robust and well known standard that is extremely reliable and fault tolerant. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ 3.2.1 ComBox-Modbus The ComBox-Modbus converts the CAN protocol used by the Elektronikon into the Modbus RTU protocol. The ComBox allows a compressor(s) to be connected to a customer’s Modbus network. The customer can then monitor all of the mission critical parameters of the compressor(s) and do some light control over his network using his plant’s DCS. The ComBox can be installed in any one of the compressors in a network. The unique feature of the MKIV CAN network is that only one ComBox is required for an installation. Please refer to section 4.3 under LAN for more information. The ComBox-Modbus needs to be programmed in the field at commissioning by an Atlas Copco Service Engineer. Please refer to the ComBox Modbus instruction manual for more details. 3.2.2
ComBox-Profibus
The ComBox-Profibus converts the CAN protocol used by the Elektronikon into the Profibus protocol. The ComBox allows a compressor(s) to be connected to a customer’s Profibus network. The customer can then monitor all of the mission critical parameters of the compressor(s) and do some light control over his network using his plant’s DCS. The ComBox can be installed in any one of the compressors in a network. The unique feature of the MKIV CAN network is that only one ComBox is required for an installation. Please refer to section 4.3 under LAN for more information. The ComBox-Profibus needs to be programmed in the field at commissioning by an Atlas Copco Service Engineer. Please refer to the ComBox Profibus instruction manual for more details. 3.2.3
ComBox-Ethernet
The ComBox-Ethernet converts the CAN protocol used by the Elektronikon into the Ethernet protocol. The ComBox allows a compressor(s) to be connected to a customer’s Ethernet network. The customer can then monitor all of the mission critical parameters of the compressor(s) and do some light control over his network using his plant’s DCS. The ComBox can be installed in any one of the compressors in a network. The unique feature of the MKIV CAN network is that only one ComBox is required for an installation. Please refer to section 4.3 under LAN for more information. The ComBox- Ethernet needs to be programmed in the field at commissioning by an Atlas Copco Service Engineer. Please refer to the ComBox Ethernet instruction manual for more details. 3.2.4
ComBox-RS232
Many occasions will arise when one will need to add an older version Elektronikon machine to the MKIV CAN. This could include not only a compressor with an older generation Elektronikon but also an ES sequencer. The ComBox-RS232 can be installed on an older version Elektronikon machine, that has an RS232 port, to convert the RS232 Elektronikon protocol to the CAN protocol. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ The ComBox-RS232 is installed on the compressor back plate of the compressor that needs the conversion. The RS232 ports of the ComBox and the Elektronikon are connected using cables and connectors supplied by others. Then the machine can be connected into the CAN network according to the standard networking connection procedures developed for the MKIV CAN system. A separate instruction is available for CAN wiring, 9820358200. 3.2.5
ComBox-DIOE
Many occasions will arise when a non Elektronikon machine would need to be added to the MKIV CAN system. This could be an electro-pneumatic regulated compressor, a MKIII LRR or a competitor’s compressor that can be controlled remotely using digital control. The ComBox-DIOE is similar to the ES001 product. The ComBox-DIOE will convert the signals to and from the digitally controlled compressor to the CAN. The ComBox-DIOE is a product that is contained in its own enclosure. It would need to be installed near the compressor being converted to the CAN. The ComBox-DIOE requires its own single phase power supply, 220/120VAC; 50/60Hz. 3.2.6
e-Box I
The e-Box I is a device that allows a user to monitor a compressor installation over the internet or his own ethernet network. The e-Box I can be connected to a MKIV CAN compressor network, up to four compressors maximum. The Web application software is embedded into the e-Box I. No controlling of the compressor network is possible. The web application software will allow a user to dial up the web address of the installation and then monitor each compressor attached to the network. The user will be able to see all of the monitoring points of the Elektronikon as well as the current status of each compressor. A user could schedule data dumps into his own database and then could trend data for maintenance purposes. The e-Box I will store data for the last 24 hours of operation. During set up of the system a user can designate three user profiles to receive automatic e-mail messages in the event of a general shutdown, general warning or service warning. In the event of a shutdown the e-Box I will store all data and compressor status for review. The e-Box I can be installed in one of the compressors and then networked to the others using the CAN. The e-Box I will require either a modem or a router to connect to the internet that is supplied by others. The e-Box I requires its own single phase power supply, 220/120VAC; 50/60Hz. See the separate e-Box I instruction manual for more details. 3.2.7
e-Box II
The e-Box II is a device that allows a compressed air installation to take advantage of the e-Services offered by Atlas Copco over the internet. The e-Box II can be installed in an installation and up to four compressors can be connected over the internet to Atlas Copco’s web site and its series of web applications. Depending on the needs of the customer several different levels of service can be offered from simple monitoring of the compressed air installation over the web to full service responsibility of the installation with close interaction to the local Atlas Copco representative. The e-Box II can be installed in one of the compressors and then networked to the others using the CAN. The e-Box II will require either a modem or a router to connect to the internet that is supplied by others. The e-Box II requires its own single phase power supply, 220/120VAC; 50/60Hz. See the separate e-Box II instruction manual for more details. H:/MAGUIRE/MKIV
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Elektronikon MKIV System Description _________________________________________________________________________________________________ 4
Control modes
The Elektronikon MKIV regulator has three distinct modes of compressor control, CCM. The compressor can be controlled locally, remotely or via a local area network (LAN). Each control mode is mutually exclusive meaning if the regulator is under one control mode it can not be controlled by another at the same time. This limitation is built in for safeguarding not only the compressor but also operating personnel. The control modes are switched manually through the faceplate of the Elektronikon by an operator. This is a different feature for the MKIV. The MKIII was switched by manipulating digital inputs of the master module by either terminal switches, LRR, or by the use of a key switch located on the cubicle door, HRR. The examples that follow are primarily for the type II and III regulators. Switching between local and remote control is also done through the regulator faceplate on the MKIV-I regulator parameter number 009. 4.1 Local control mode When the compressor regulator is in local control mode the regulator will indicate this by displaying the following screen:
↑
CCM Local control Menu F1
Mod F2
↓ F3
The compressor control mode, CCM, is displayed in the Configuration subsection of the Modify settings section. When the CCM is set for local the compressor can only be controlled locally or at the Elektronikon faceplate by an operator. This would normally mean the starting, stopping, loading or unloading of the compressor by an operator through the faceplate of the Elektronikon. In local control the compressor will acknowledge and execute a remote emergency stop command. The loading and unloading command can also be excuted by an external pressure sensing device, such as a pressure switch or ES100, if “remote pressure sensing” input to the Elektronikon is bridged. See figure six as an example. In this situation the normal loading and unloading of the pressure band programmed into the regulator is ignored and the regulator looks at the status of the remote load/unload input. The compressor will load if this input is closed and unload if this input is open. The Elektronikon DSS function is disabled when remote pressure sensing is active and the motor idling time is a function of the number of motor starts per hour that is programmed into the regulator. This remote pressure sensing feature is not included with the Elektronikon MKIV-I regulator. Any digital input wired into the Elektronikon must be a voltage free contact.
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Elektronikon MKIV System Description _________________________________________________________________________________________________ 4.2 Remote control mode When the compressor regulator is in remote control mode the regulator will indicate this by displaying the following screen:
↑
CCM Remote control Menu F1
Mod F2
↓ F3
The compressor control mode, CCM, is displayed in the Configuration subsection of the Modify settings section. When the compressor is under remote control it will only acknowledge start/stop, load/unload commands through digital inputs into the Elektronikon. These inputs are typically switches from a remote operator station or relay contact outputs of a customer’s DCS. It will acknowledge and execute a local emergency stop command issued by an operator that pushes the E-stop switch located on the compressor cubicle door. Remote pressure sensing can also be configured as described above. Refer to figure six for details. The MKIV-I can only receive a remote start/stop or E-stop command. It does not have the remote load/unload or remote pressure sensing capability of the type II and III regulators. Any digital input wired into the Elektronikon must be a voltage free contact. 4.3 LAN control LAN control means that the control decisions for the regulator is being taken care of by the LAN, local area network. For the purposes of the Elektronikon MKIV-II and III only this means either control by the MKIV’s MCC feature or by a customer’s distributed control system, DCS, over their network using one of our protocol conversion ComBoxes. The Elektronikon MKIV regulators, not MKIV-I, all have a fieldbus port built in as standard. The fieldbus used by the MKIV is called CAN. CAN, Controller Area Network, is an ISO approved standard communication protocol that was developed in 1984 by Bosch for in vehicle data transmission. It is a very robust and well known standard that is extremely reliable and fault tolerant. LAN control is not available on the MKIV-I regulator. 4.3.1
LAN control – customer network
If a customer would like to control the compressor from a remote location via a computer, or DCS, they must convert the protocol used by Atlas Copco to the protocol being used locally. Typical examples of protocols used are Modbus and Profibus and the ComBoxes available are described in section 3.2. Under this scenario the customer can do limited compressor control, starting, stopping, loading or unloading. They can also incorporate the compressor into their plant monitoring system by having their systems integration engineering staff read the desired data from the compressor over their network connection and display the data in their plant’s monitoring software application. See figure three for a graphical representation of how the regulators can be incorporated into the customer’s plant wide network.
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Networking of Atlas Copco compressors can be done with any generation of Elektronikon or electropneumatic regulated compressor. To make it simple all connected compressors must be brought some how over to the CAN. A series of ComBoxes has been developed to do this please refer to section 3.2. A detailed document has been prepared by our Service Department that explains in detail the methods required to install a successful CAN, 9820358200. 4.3.2
Local area network – MCC
One of the best features of the new Elektronikon MKIV-II and III is a feature called MCC. MCC stands for multiple compressor control. MCC is carried out over the CAN port included with every MKIV-II and III regulator. MCC is not available for the MKIV-I regulator as it does not have a CAN port. To activate the MCC function for an installation a hardware activation key called a Dongle is required. The Dongle is installed in the expansion port on the back of the master module or the 3x4 port of the last expansion module in an ES system. See figure seven. The MCC feature allows the networked control of between two and four compressors. The objective is to maintain the net pressure between a given pressure band and also equalize the running load of the attached compressors. It has the same basic features of the ES 100 where the primary benefit to a customer is that the overall pressure band of a system can be greatly reduced over what it would be with other sequencing methods such as a cascading pressure band set up. It is possible to integrate one Atlas Copco VSD compressor into the MCC network. If more than one VSD is installed in a network the VSD with the lowest ID address is accepted into the MCC and the other VSD(s) are placed under local control. The compressor regulator that is designated as the master continues to perform the actions required to regulate its own compressor and act as the master in the MCC. All of the other regulators that are attached act as slaves in the network. All generations of Elektronikon as well as electropneumatic regulated compressors can be connected to the CAN and be integrated into the MCC. Competitors electropneumatic machines may also be integrated if they have remote start/stop and remote load/unload capability. Some local engineering may need to be considered and this should be handled on a case by case basis. Refer to section 3.2 for details on the methods available to connect different machine regulation schemes to the CAN. The MCC control algorithm is based on the primary principles of maintaining the air net within the programmed band and equalize the running hours on the machines attached. The MCC will start and load the machine with the lowest number of running hours. It will unload and stop the machine with the highest number of running hours. If a VSD is present it will start the VSD machine first. The MCC will force the setpoint of the VSD to the middle of the pressure band programmed in the master. The VSD’s indirect stop level will be set at the Pmax level of the MCC pressure band. Decisions to start and load the next load/unload machine will only happen when the VSD at its maximum speed. Decisions to unload and stop the load/unload machines happens when the VSD regulates down to its minimum speed. The status of the attached compressors is read at the master’s LCD. With stable air nets the logical sequence shift of machines can be manually or timer forced. For more detailed information regarding the MCC please refer to the MCC manual.
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Elektronikon MKIV System Description _________________________________________________________________________________________________ 5
Communication
The Elektronikon MKIV has two methods of communication available that allows a user to keep an eye on the status and health of the compressor being controlled. Digital and network communication. 5.1
Digital communication
In the context of this discussion we define digital communication as feedback from the compressor in the form of voltage free auxiliary relay contacts. Digital then means the simple opening and closing of a relay contact or switch that a user could then wire into a PLC or light an indicator light or sound an alarm in a control room in a remote location. The MKIV regulators all have auxiliary relays identified as K01 through K09 for example. Most of the functions of these relays are fixed and are used by the compressor control circuit to start and stop the motor or load and unload the compressor. The MKIV regulators have several auxiliary relays that are not used by the compressor control circuit and are intended to be used by the customer for remote annunciation of certain events. The type I regulator has one auxiliary relay available called general shutdown, K06. The type II and III regulators have three auxiliary relays available. Air pressure high/low, K05, tracks the status of the unload or load setting that is programmed into the Elektronikon. It is used with sequencer products RD 72 or ES 100 (digital control). Think of it as the contacts of a pressure switch that indicate when the unload or load settings have been reached. Automatic operation, K07, indicates that the compressor is under automatic control or is deciding on its own to load or unload the compressor based on its programmed pressure band. The compressor is under manual control when a manual unload command is issued or a manual stop command is issued. General warning, K08, indicates that either an analogue value being measured is drifting towards shutdown, such as the element outlet temperature, or service is required. General shutdown, K09, indicates that the machine has shutdown due to a protection setting or E-stop command. All of this digital communication is standard. Any digital contacts either input or output wired into the Elektronikon must be a voltage free contact. 5.2
Network communication
Network communication is the monitoring of the compressor via a computer network. This can be done using a customer’s DCS and one of our protocol conversion options or by installing one of the e-Box products. The networking to the individual regulators is done over the CAN. See sections 3.2 for more details.
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Table one – Standard sensor config uration
Figure one - MKIV with expansion modules
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Figure two – CAN network
Figure three – customer LAN connections
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Figure four – e-Box I graphical representation
Figure five – e-Box II graphical representation
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Elektronikon MKIV System Description _________________________________________________________________________________________________ Figure six – digital input for MKIV-II or III
Figure seven – MCC activation key the Dongle
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