DAB 84
Contents
1. The unit acquires the data and convert them in a message packet that may be sent to another similar unit through a RS 485 Serial Port both in Wire and Wireless Mode using an adequate Radiomodem The unit can also receive a message packet from the serial line and convert it into a analogue and or digital data available at the respective outputs The communication timing is expressly designed for the Wireless communication naturally slower than cable commu nication and the transmitted or received packet must be in the 9 600 bps 8 data bits No parity and 1 Stop bit format The serial port speed is internally set and it s generally suitable for both wire and wireless communication The DAB 84 card presents four Digital Inputs two Analog Inputs and consequently four Digital Outputs and two Analog Outputs A digital Alarm Output and the RS 485 Serial Port completes the unit The Alarm Output is activated by a fault in communication and it s automatically reset when a normal communication is restored Please see the paragraphs 5 2 3 and 5 2 4 for the Alarm functionality and setting The DAB 84 card may be connected to others DAB 84 to expand both digital than analogue inputs if necessary The connection between the principal unit generally called Master and the Expansion units is made by a flat cable connection used also to connect the Master with a generic Auxiliary unit A maximum of three expansion cards and one Auxiliary card may be connec2. Data Speed 9 600 bps 1 200 to 19 200 bps on request Bit di Dati Data Bits number 8 bit Bit di Start Start Bits number 1 bit Parita Parity Bit value Nothing E ven or O dd on request NOTES 1 Due to the presence of the switching supply units the power consumption is practically constant respect to the supply voltage variations 2 Indicates the power consumption with all inputs and outputs idle and with all transducer and serial port disconnected At voltage V the idle current consumption can be calculated by I P V For example at V 12 Vdc the related idle current is I 0 72 12 0 06 A 60 mAdc 3 All alternating voltages and currents are intended RMS sinusoidal at main frequency of 50 or 60 Hz Lower main frequency are not admitted 4 The input impedance determines the current consumption of the digital input It varies from 1 9 to 12 mAdc allowing the input driving by an electronic device such as an Open Collector transistor or an Open Drain Mosfet 5 The analog input impedance is the sum of the sampling resistor 60Q plus the dc resistance of the noise filter inductor 2 5Q and the dc resistance of the fuse 15Q The sampling resistor tolerance is 1 6 The analog outputs are linear in the 2 20 mA range so it s possible to show the transducer failure condition or the Open current loop condition 7 Each analog output is equivalent to a Current Generator and the Vo an value indicates its operating voltag
3. active Not active 5 2 1 Point to Point and Point to Multipoint address configuration The communication mode is selected by the address set in the card This address is set by the dipswitches Nos 1 2 3 4 and 5 as above explained In this bank the LSB is the dipswitch No 5 and the MSB is the No 1 The following Table 7 shows the dipswitch set as function of the desired address As is shown the dipswitches Nos 5 and 4 are used in the expansion card as an internal address to select both inputs and outputs Table 7 Setting of the addresses dipswitches Address Dip1 Dip 2 Dip 3 Dip 4 Dip 5 Notes 0 OFF OFF OFF OFF OFF Set Point to Point communication mode 1 OFF OFF OFF OFF ON Multipoint mode Expansion card internal address 2 OFF OFF OFF ON OFF Multipoint mode Expansion card internal address 3 OFF OFF OFF ON ON Multipoint mode Expansion card internal address 4 OFF OFF ON OFF OFF Multipoint mode 5 OFF OFF ON OFF ON Multipoint mode 6 OFF OFF ON ON OFF Multipoint mode 7 OFF OFF ON ON ON Multipoint mode 8 OFF ON OFF OFF OFF Multipoint mode 9 OFF ON OFF OFF ON Multipoint mode 10 OFF ON OFF ON OFF Multipoint mode 11 OFF ON OFF ON ON Multipoint mode 12 OFF ON ON OFF OFF Multipoint mode 13 OFF ON ON OFF ON Multipoint mode 14 OFF ON ON ON OFF Multipoint mode 15 OFF ON ON ON ON Multipoint mode 16 ON OFF OF
4. and aren t accepted The addresses range of the ModBus function is automatically ex tended at the connection of one or more expansion cards depending on their number For example the addition of one expansion card automatically set the address range from 0 to 7 instead of from 0 to 3 The address assigned to the expansion card must be the lowest possible depending in the number of connected expansions so for example the 1 expansion card will have the address 1 the 2 the address 2 and so on This isn t a request of the Master unit but of course it s the simplest method to assign the addresses The following Table 2 shows the equivalence between the addresses of the Input Registers and Holding Registers functions in the ModBus protocol and the Analog Inputs and Outputs of the DAB 84 card Table 2 Equivalence between the addresses of the Input and Holding Registers function and analog I O of the DAB 84 Address Analog Input Analog Output 00 Input 1 of the Master Output 1 of the Master 01 Input 2 of the Master Output 2 of the Master 02 Input 1 of the 1 expansion card Output 1 of the 1 expansion card 03 Input 2 of the 1 expansion card Output 2 of the 1 expansion card 04 Input 1 of the 2 expansion card Output 1 of the 2 expansion card 05 Input 2 of the 2 expansion card Output 2 of the 2 expansion card 06 Input 1 of the 3 expansion card Output 1 of the 3 expansion card 07 Input 2
5. of the 3 expansion card Output 2 of the 3 expansion card Also for these functions are valid all considerations explained for addresses assignment of the Discrete Inputs and Coils function To utilise the DAB 84 cards with the ModBus protocol it s necessary to install in the Central unit of the system a dedicated software supporting this communication protocol Are available a lot of versions of SCADA software supporting the ModBus protocol configurable practically for all the applications Page 4 of 9 ERE S n c 2 0 Technical Data DAB 84 Instruction Manual Revision 3 0 In the following paragraph are listed the technical data of the DAB 84 card 2 0 1 Absolute maximum ratings These values indicate the maximum value that each parameter can assume and their overcoming can damage irreversibly the device or cause an operating condition beyond the safety condition with a considerable reduction of the reliability of the whole system The following Table 3 shows these maximum ratings Table 3 Absolute Maximum Rating of the DAB 84 card Parameter Description Value Vs Supply Voltage 36 Vde Is Current consumption 500 mAdc Ian out Output current of the analog sensor supply 35 mAdc Tan inp Analog Input current 60 mA continuous 325 mA for 0 1 seconds Vo AN Voltage drop of each Analog Output 36 Vde V0 AN INS Insulation between Analog Outputs and ground 50 Vd
6. the Digital Inputs and Outputs of the DAB 84 card Table 1 Equivalence between the addresses of the Discrete Inputs and Coils functions and digital I O of the DAB 84 Address Digital Input Digital Output 00 Input 1 of the Master Output 1 of the Master 01 Input 2 of the Master Output 2 of the Master 02 Input 3 of the Master Output 3 of the Master 03 Input 4 of the Master Output 4 of the Master 04 Input 1 of the 1 expansion card Output 1 of the 1 expansion card 05 Input 2 of the 1 expansion card Output 2 of the 1 expansion card 06 Input 3 of the 1 expansion card Output 3 of the 1 expansion card 07 Input 4 of the 1 expansion card Output 4 of the 1 expansion card 08 Input 1 of the 2 expansion card Output 1 of the 2 expansion card 09 Input 2 of the 2 expansion card Output 2 of the 2 expansion card 10 Input 3 of the 2 expansion card Output 3 of the 2 expansion card 11 Input 4 of the 2 expansion card Output 4 of the 2 expansion card 12 Input 1 of the 3 expansion card Output 1 of the 3 expansion card 13 Input 2 of the 3 expansion card Output 2 of the 3 expansion card 14 Input 3 of the 3 expansion card Output 3 of the 3 expansion card 15 Input 4 of the 3 expansion card Output 4 of the 3 expansion card As appears from the above table in presence of the only Master unit only the addresses from 00 to 03 are valid while the following ones are illegal
7. ERE S n c DAB 84 Instruction Manual Revision 3 0 DAB 84 Analog and Digital Data Acquisition and Reproduction Card Instruction Manual General Index crase EE E EEEE EEEE NEEE ENERE REEE S EENE EEES EE REKE ER page 1 1 0 General Tntormations eiiiccec io cesses cciskecesccesncheccceatadcctace sadevccdelinaii sect suaces tocuvdsceass tae saccuboseuisbedecccsuaeeacteuncacedennesd page 1 0 1 CE conformity ssccsciscc ds cs cecedessig tack sanedies enee dan ATOPAR EI UNITO ANENE OENE EONS E eA ENEP UNESE AAEN ESETE TESSO sii page LP Communication MOGES sssrin arn RN EE E aa AE NEEE KOSSE PaaS Erpen page 1 1 1 Point to Point communications aE EEA EEE E A E E E Ee page 1 1 2 Point to Multi Point communication with ModBus protocol in RTU mode ccccceeceeseeseeeceeseeeeeeaeeeees page 2 0 Technical Data 2 0 1 Absolute Maximum Ratings e eeeeeeeeeeeeeeeeeesereertsistsisterrrestststetaterareristsiststettureststatntatettntstststetetteestsratetntestnee 2 0 2 Operating Characteristics ss czsiacs ccisisisstcapeasnssepedsicdaheas coteraigaedgs ne sues cpadecsteneap aisyodscadaxetsnecaislsasdaieaa cgbepspeaissasnetartiace 3 0 Circuit description is sso ce5 shes shies sac ck e a aai e E Ea E SEAE A aaa aTa 3 0 1 WControll r SECON 5 3 sicisiscossssesesasisizsciusoosynssssasessvinay coveesendsans Ea riers de s E ATEO ESETNEK ESENTE E ETSEAN S SAE Eni 3 0 2 Inputs and outputs digital interfaces and RS 485 Serial Port interface 3 0 3 Ana
8. F OFF OFF Multipoint mode 17 ON OFF OFF OFF ON Multipoint mode 18 ON OFF OFF ON OFF Multipoint mode 19 ON OFF OFF ON ON Multipoint mode 20 ON OFF ON OFF OFF Multipoint mode 21 ON OFF ON OFF ON Multipoint mode 22 ON OFF ON ON OFF Multipoint mode 23 ON OFF ON ON ON Multipoint mode 24 ON ON OFF OFF OFF Multipoint mode 25 ON ON OFF OFF ON Multipoint mode Page 7 of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 Address Dipl Dip 2 Dip 3 Dip 4 Dip 5 Notes 26 ON ON OFF ON OFF Multipoint mode 27 ON ON OFF ON ON Multipoint mode 28 ON ON ON OFF OFF Multipoint mode 29 ON ON ON OFF ON Multipoint mode 30 ON ON ON ON OFF Multipoint mode 31 ON ON ON ON ON Multipoint mode 5 2 2 Configuration of the repetition times in automatic sending condition In the Point to Point communication mode it s available the periodic sending of a message to read or set the status of all the analog and digital inputs and outputs The time period is set by the dipswitches Nos 8 7 and 6 in which the dip No 8 is the LSB while the dip No 6 is the MSB The following Table 8 shows the dipswitches set as function of the desired repetition time Table 8 Setting the time repetition dipswitches in Point to Point mode Repetition Dip 6 Dip 7 Dip 8 Notes Time No repetition OFF OFF OFF Starting message by the change in
9. a digital input status 1 second OFF OFF ON Periodic sending and by digital input status change 5 seconds OFF ON OFF Periodic sending and by digital input status change 30 seconds OFF ON ON Periodic sending and by digital input status change 1 minute ON OFF OFF Periodic sending and by digital input status change 5 minutes ON OFF ON Periodic sending and by digital input status change 20 minutes ON ON OFF Periodic sending and by digital input status change 60 minutes ON ON ON Periodic sending and by digital input status change NOTE 1 The status change originating a message transmission may be occur on one of any digital inputs Independently from the Repetition time setting the message is sent or at the repetition time expiry or when a digital input changes its status The Analogue inputs cannot start a message transmission To avoid collisions between messages in the Point to Point mode one of the two cards must be set without repetition time In fact if enabled the two repetition times are equals or one can be chosen as an integer multiple of the other so the collision probability may be high The unit in which is set up the repetition time must be placed into the control centre of the network In this way the Communication Alarm can be monitored and managed under necessity The choice of the repetition time depends on the application and must be selected as function of the variation speed of the measured paramete
10. e Io pvic Digital Outputs Current max relay current 3 Adc Aac Vo pIG Voltage across Digital Outputs 250 Vde Vac V o0 DIG INS Insulation between Digital Inputs and or ground 250 Vac Vipic Voltage at the Digital Inputs 30 Vde Vac V LDIG INS Insulation between Digital Inputs and ground 40 Vdc Vac To rs4gs RS 485 Serial Port current 85 mAdc Vasass cnp__ Voltage between RS 485 Serial Port and ground 7 12 Vde NOTES 1 Available current to energise a two wire 4 20mA transducer The no load voltage is of 15 65 0 25 Vdc with an internal resistance of 47 Q 2 Each Analog Input is protected against overcurrents by a Fast Blow fuse of 50mA in 5 x 20 mm 0 2 x 0 8 inch format This fuse never must be replaced with an higher current one to avoid the destruction of the precision Current to Voltage converter 3 4 supply voltage of the analog output Maximum voltage across the Analog Outputs Neglecting the voltage drops across the cables and the receiver input this is the maximum The maximum current flowing into each Digital Output depends on the load typology In direct current are allowed the following values 3A 30V 0 35A 110V 0 2A 220V In single phase alternate current at 220Vac are allowed the following values 3A cosg 1 1A cosg 0 2 The maximum switchable power of a single phase squirrel cage asynchronous motor is 100 VA 5 ground 2 0 2 Operating characteristics At nominal lin
11. e load of 60 Q The interface chip determines both the maximum outgoing current and the maximum voltage between inputs and The following Table 4 shows the recommended operating characteristics of the DAB 84 card Table 4 Recommended operating characteristics of the DAB 84 card Parameter Description Value Notes Vs Supply Voltage 9 30 Vde Negative pole connected to ground chassis r I 7 Is Current consumption lt 500 mA_ Single card all I O activated at 8 Vdc supply x A 3 x Pav Idle power consumption 720 mW _ Single card all I O idle Saas 7 3 a 5 7 Vi pic Digital Inputs applicable Voltage 5 24V AC DC separated inputs without common polarity Zi pic Digital Inputs internal impedance 2kO Resistive with radio frequency internal filter Tan inp Analog Input Current 0 20 mA_ Referred to ground negative pole of the supply 5 3 ZAN INP Analog Input Impedance 78 Q 30 Across the input and ground V AN INP Analog Input Voltage 0 1 62 V_ Measured across input and ground Vo pic Digital Output Voltage 220 Vac de Separated outputs protected by 275Vac varistor To pic Digital Output Current lt 3 Aac de Depending on load type See 2 0 1 note 4 6 To an Analog Outputs Current 4 20 mA _ Separated outputs and insulated respect ground 3 7 z Vo AN Analog Outputs compliance 8 30 Vdc Separated outputs and insulated respect ground Baud Rate
12. e range Due to the passive two wire configuration each output is energised by the current loop therefore this value indicates the voltage drop across the output This voltage increased by the cable losses and the input voltage across the external current voltage converter de termines the minimum supply voltage must be applied at each analog output Page 5 of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 3 0 Circuit description The DAB 84 unit contains a wController section a Digital Input and Output Interface section an Analog Input and Output Interface section and finally a Power Supply section to energise all the others 3 0 1 Controller section It utilise a PIC18F4423 micro controller energised at 5 Vdc to allow the acquisition and reproduction of all digital and or analog data the data communication through the RS 485 Serial Port directed to the external Radiomodem or DTE the data communication with the expansions and auxiliary card if presents and finally manage the ModBus protocol 3 0 2 Inputs and outputs digital interfaces and RS 485 Serial Port interface The digital inputs are connected through AC opto couplers while the digital outputs and alarm output use a Relay contact A dedicated RS 485 interface chip is used in the communication port The use of a relay contact into all digital outputs permit the direct actuation of a small or medium loads using the single phase AC mains at 115 230 Vac with 3 A of
13. ire sensor therefore an external supply source is required for their operation 3 0 4 Supply section The utilisation of a switch mode supply unit allows the card to accept a supply input voltage in the range from 8 to 36 Vdc The negative pole of the supply is connected to ground and to the metallic chassis The first internal switch mode supply reduce the input voltage to 5 Vdc to energise the micro controller and digital interface sections A second switch mode supply unit generate the supply voltage of the current to voltage converter and the external transducers The supply section is protected against polarity reversal and against over current using a series diode and a fast blow fuse The energy consumption depending on the status of digital outputs is practically constant in the whole input voltage range and the maximum current consumption occurs at the minimum supply voltage 4 0 Connections All supply analog and digital inputs and outputs alarm output and RS 485 serial port connections are realised with screw connectors The connectors for expansions and auxiliary cards are located on the sides of the box and they are a male holder for flat cable female connector These flat cable carries the communication line between the master unit and the expansions auxiliary card and the supply lines in order to simplify the wiring NOTE To avoid any problem of short circuits between any input output contact and or between any contacts and the g
14. is time is not compliant with the safety directives because is too long therefore the DAB 84 must not be used as control system of any devices mechanical electrical and so on that could create risks for the operator safety The Communication Alarm is automatically deleted when is restored a regular communication so all outputs forced to 0 if the Safe Mode is enabled come back to the correct value restoring the system operation As well for this reason the DAB 84 must not be used to control devices that may be potentially dangerous for the operator safety 6 0 Mechanical characteristics The whole apparatus is closed in an anodised Aluminium box with a Plexi glass cover fixed with four knurled knobs On the bottom side of the box a DIN Guide bracket is present to allow a simple insertion in the related Q DIN guide The weight of the apparatus is 15 16 0 3 oz av The following Figure 1 shows the outline drawings of the DAB 84 Fig 1 DAB 84 outline drawings No knurled knobs lt lt pi po fan lf ary P DIN GUIDE BRACKET S No 09 0002 B G A lm lm SO aa a a a bs eae RS 485 AN 1 AN 2 0 0 1 0 0 2 0 0 3 0 0 4 ALARM OOO PRIMA DI APRIRE TOGLIERE L ALIMENTAZIONE DAB 84 TURN OFF BEFORE REMOVE THIS COVER DATA ACQUISITION amp w SEE MANUAL FOR DETAILS cm blsecaseeat c O000000000 ANALOG ANALOG DIG DIG DIG INPUT1 INPUT2 INP 1 INP 2 INP 3 Zz 2s E R E S n c Ital Via Ermanno Ge 9 11 27049 S
15. log Inputs and Outputs interfaces 0 0 0 eee ce esecseeeeeeeececeeesessceeeeesecsesaessesaeeesessesaesaessesaseeseessesateaseas 3 0 4 Supply SCCUOM 5isi5 scssccsces ss ciscaseiscsasstvessancaasasscentatsanies sasessat E TAT AO Connections 53 5c 525 556i sta sucin ech shel mesa ind ikke sat cbedavsabavbabssdsubosssiiapabedstenyeaubebast TO AET EEE OE TEE TE A EEEE 5 0 Configuration of the unit by Dipswitches and Jumper c ccceeccessceceseeeeeeceeeeeeneeceeeeseneecneeeeneeeees 5 1 Master Expansion configuration Jumper ccecceeeeseeeeereeee 5 2 Dipswitches ss 0ssceccsciessisisisieisiavasevtersescnsseveizecee 5 2 1 Point to Point and Point to Multipoint address configuration 5 2 2 Automatic sending repetition time configuration 5 2 3 Safe Mode configuration 2 0 0 0 ee sessesesseeeceeeeecsersneseeeeeeceeseseeeneeaees 5 2 4 Communication Alarm functionality and its delay time configuration 00 0 cc eee ceeeeeeeeeteeeneeeees 6 0 Mechanical Character iste s0 ccs cessscesie8 ievsecssaevenescisssvocescenssndendenssubcansenisenicepesevaceodevsbsvbstvabessieebsvesnevacsaan page SMWMMANINNIANDNDDADAADAADAUUAMHYNHN NN WN Page of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 1 0 General Informations The DAB 84 card permits the Data acquisition both analogue and digital and the related reproduction respectively at dedicated inputs and outputs
16. n Safe Mode Alarm Delay position Mode Serial Port Time MST Master Active Unit identifier from 0 to 31 Active Available Available EXP Expansion Inhibited _ Internal Identifier from 1 to3 Inhibited Inhibited Inhibited In the expansion mode the data communication between the Master unit and all expansion cards travels over a communication port on the flat cable while the RS 485 serial port is completely inhibited and must not be connected In the following paragraphs are explained the addressing the safe mode and the alarm delay configuration 5 2 Dipswitches This dipswitches bank allows the configuration when the card is set as Master Each dip is active if it is in ON posi tion and their functions are shown in the following Table 6 Table 6 Function of each dipswitch Position Binary Function Master Expansion Weight Point to Point Point toMultipoint Any modes Dip 1 16 Addressing OFF To be set depending Not active Dip 2 8 Addressing OFF on the desired address Not active Dip 3 4 Addressing OFF Value range from 1 to Not active Dip 4 2 Addressing OFF 31 as explained in the Expansion Address Dip 5 1 Addressing OFF following Table 7 value range from 1 to 3 Dip 6 4 Time selection Set the repetition time Dip 7 2 Time selection as explained in Table Not active Not active Dip 8 1 Time selection 8 Dip 9 1 Safe Mode Selectable Not active Not active Dip 10 1 Alarm Delay Selectable Not
17. ntil the following sending originated by the repetition time expiry if no one change occurs or before at the changing of anyone of the digital inputs In this case the periodic repetition counter is reset and restarts from this moment If for any reason a correct answer is not detected the unit come into the repetition procedure in which the message is repeated in groups of three close transmissions spaced of 30 seconds The repetition time interval between the three sending depends on the periodic repetition time selected in the dipswitches bank If this time is of 1 second the repetition time interval is set to 1 second while for higher values it is set to 4 seconds A communication fault Alarm is activated after 3 or 9 failed transmissions depending on the dipswitch No 10 setting as explained in the 5 2 4 The expansion cards will be used if the required number of analog and or digital inputs outputs exceed the available on a single card In this way it s possible to obtain until 8 analogue inputs and outputs and 16 digital inputs and outputs These additional cards must be configured as Expansions using the lateral Jumper as explained in the 5 1 The serial ports RS 485 of these additional cards are inactive because the communication process is managed by the Master unit so the serial ports of any expansion cards must be unconnected As the Master unit also the expansion unit has an Internal Identification Addres that may be set u
18. o permit its updating The addresses range follows the rules explained for the Read Coils function and of course to update each digital output it s necessary to write each register one at a time specifying the correct address F 0x06 Write Single Register It permits to write the value stored in each Digital to Analogue converter to permit its updating The same rules explained for the addresses range of the Read Holding register function must be ap plied to this function and of course the register updating requires the indication of the address of the register to be updated G 0x0F Write Multiple Coils It permits to write an ensemble of Digital Outputs sending only one message Of course the addresses of the ensemble of Digital Output to be written must be specified into the message The ad Page 3 of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 dresses range of this function is the same of the Read Coils function H 0x10 Write Multiple Register Similarly to the Write Multiple Coils function it permits to write an ensemble of Digital to Analog converters sending only one message As above specified the addresses of the ensemble of DACs to be written must be indicated into the message The addresses range of this function is the same of the Write Single Register function The following Table 1 shown the equivalence between the address of the Discrete Inputs and Coils functions in the ModBus protocol and
19. operating into the peripherals and it doesn t appear in the address of the query sent from the central unit of the network but it permits the correct writing or reading of the inputs outputs of the expansion cards in each peripherals The functions available from the ModBus protocol used in the DAB 84 units are the following A 0x01 Read Coils It permits to read the status of the Digital Outputs In system with a single DAB 84 the ad dressing range of this function covers the 0 to 3 range Each additional expansion adds 4 addresses so a complete system operates with a function range from 0 to 15 B 0x02 Read Discrete Input It permits to read the status of the Digital Inputs The addressing range of this fun ction follows the same considerations explained for the Read Coils function C 0x03 Read Holding Register It permits to read of the values stored in both Digital to Analog converters that drive the Analog Outputs The addresses range of this function covers the 0 to 1 range and as explained for the previous functions each additional expansion adds 2 addresses so a complete system operates in the range 0 to 7 D 0x04 Read Input Register It permits to read the value of the Analogue Inputs after the Analogue to Digital conversion The addresses range of this function follows the same rules explained for the Read Holding Register function E 0x05 Write Single Coil It permits to write each Digital Outputs t
20. peak current 3 0 3 Analog Inputs and Outputs interfaces The DAB 84 accept analog input signals in the 0 20 mA standard and reproduce the analog signals in the 2 20 mA probably the most used system to carry analog signals in the industrial environment for its great advantages respect to the line attenuation the noise interference and errors The extension of the input current range and the linearity of the analog output in the 2 20 mA range allows the transfer of the Open Loop Transducer failure condition as in a wired system Each input contains a precision Current to Voltage converter to translate the 0 20 mA into the 0 5 Vdc required by the 12 bit analog to digital converters into the micro controller and is protected against over current by a 50 mA fast blow fuse The input impedance of each input referred to ground is of 78 3 Q and causes a input voltage drop of 1 56 Vde 60 mVdc The Analog Outputs receive the data to be send in digital format and convert it in analog 2 20 mA format using a 12 bit serial DAC and a high precision voltage to current converter Since both analog outputs draws their supply from the current loop the the current never can be null The minimum current in the loop can be measured after the turning on transient or after a manual reset This value is generally included in the 350 1 000 uA range Each analog output is insulated respect both the other and to the ground and it s equivalent to a passive two w
21. r For example if this parameter is analog the repetition time must be sufficiently short to follow correctly the input variations These time intervals are set into the firmware of the Controller and may be suitable for the majority of the applications On request they may be changed to allow the maximum functionality 5 2 3 Safe Mode configuration The dipswitch No 9 in ON position enables the Safe Mode operation In this operating mode at the fall of the communication all outputs are forced in the 0 condition i e all digital outputs are Open and all analogue outputs are set to 0 equivalent to an output current of 0 mA and at the same time the Communication Alarm output is activated As appears in the Table 8 the minimum time of 1 second is not compliant with the directives on the Human Operators security therefore this device must not be used to control any mechanical device that could create a risk for the operator In the following 5 2 4 are shown more information on the Communication Alarm 5 2 4 Communication Alarm functionality and its delay time configuration This paragraph it s very important for the use of the DAB 84 unit because explains the functionality of the Commu nication Alarm and the reason because this device must not be used to drive any device that could create a risk for human security In the Point to Point mode both unit are able to show the Communication Alarm when for any cause the communica
22. round it s important to use adequate wire termination in particular if a stranded wire is used During the wire clamping do not apply an excessive pressure and torque on the screw connector to avoid damages to both the printed circuit board and to the screw connector 5 0 Configuration of the unit by Dipswitches and Jumper The operating mode of the DAB 84 card is selected by the Dipswitches bank and the lateral Jumper 5 1 Master Expansion configuration Jumper This jumper is located on the right side of the box near the auxiliary card connector and allows the configuration of the card as Master or as Expansion moving the short circuit jumper to the required position If configured as Master the card is completely independent and all its features are available otherwise as Expansion the card must be connected to a Master unit and some features as for example the alarm output the RS 485 serial port communication are inhibited and also the Dipswitches changes their functionality A single card must be always set as Master and this is the default setting after the production testing The following Table 5 on page 7 shows the operating condition of the DAB 84 card in both Master and Expansion configuration Page 6 of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 Table 5 Features of the unit as function of the Master or Expansion configuration Jumper Operating RS 485 Addressing Repetitio
23. sing the dip Nos 5 and 4 of the dipswitches bank It s important to notice as this address is not the same of the address utilised by the Master Unit but in this case may be considered as a sub address for the data sent into the correct expansion card The setting of these addresses is explained in the 5 2 Activating an input in the local unit the communication logic activates the homologous output in the remote unit and vice versa This procedure is even valid when in both local and remote units are present one or more expansions 1 1 2 Point to Multi Point communication with ModBus protocol in RTU mode In a Point to Multipoint network the central unit is a intelligent DTE such as a Computer or a PLC unit The com munication begins always from the central unit and all peripherals are used as slaves and cannot begin a communi cation Generally the central unit uses a Polling to enquire each peripherals using a ModBus protocol in RTU Mode In the simplest case each peripheral unit consist in one DAB 84 card that must be set with an Identification Addres from 1 to 31 using the Dipswitches bank as explained in the 5 2 1 A peripheral may be realised also with more than one DAB 84 card if is necessary an higher number of analog or digital inputs or outputs These additional cards must be set as Expansions and must have an Internal Identification Address set from 1 to 3 as specified in the 5 2 This Internal Identification Address is
24. ted to the Master unit To simplify the wiring this flat cable includes the supply and the manual reset lines besides the data line It s possible realise both Point to Point than Point to Multipoint communication networks In the last case a ModBus protocol in RTU mode is implemented for communication The card configuration is realised by a Dipswitches bank and a selection Jumper The card is contained in an anodised Aluminium box covered with a transparent Plexi glass panel The metallic box is electrically connected to the negative pole of the supply input In according to the safety rules this metallic box and consequently the negative pole of the supply must be connected to ground In the bottom of the enclosure is mounted a metallic locking system to fix the device onto a Q Din Guide NOTE This device is not compliant with the Directives on the Human Operators Security so it cannot be used to drive any device mechanical electrical and so on that may create a situation of risk to an operator 1 0 1 CE conformity The DAB 84 card is in according to the CE directory under the following directives and related modifications 2006 95 CE Low Voltage Directive 2006 42 CE Machinery Directive 2004 108 CE Electromagnetic Compatibility Directive Moreover in the development of the homologation procedures have been applied all the following norms and or technical requirements IEC 61326 1 EMC requirements EN 61010 1 Safe
25. tion between the units stops for example for an interference in the radio channel When a message is sent the sending unit waits an answer from the other unit independently from the cause that originate this transmission repetition or status change of a digital input If the communication is regular an answer message comes from the other unit so that the repetition cycle proceeds under the time set by the dipswitches If there isn t an answer the unit repeats the message twice waiting the answer and in its absence the sending unit sends again the message after 30 seconds In absence of the answer this cycle is continuously repeated and after 9 attempts and a total time in the range from 1 minute and 9 seconds up to 1 minute and 36 seconds depending on the selected repetition time will be activa ted the Communication Alarm Page 8 of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 The dipswitch No 10 set the delay time before the activation of the Communication Alarm If the dip is in OFF position the alarm is activated after three attempts otherwise in ON position it is activated after the 9 If the repetition time is less than 1 minute the dip No 10 must be in the OFF position to avoid excessive delays Because the Communication Alarm controls the status of both analog and digital outputs if the Safe Mode is enabled appears evident as the minimum time before the activation of the Safe Mode is of about 3 or 12 seconds Th
26. tradella PV DAB 8 Plan and frontal view Title Scale 1 1 DAB 84 Outline drawings Sze Doc Nunber Re All measures are in inches oaks DABSYMCE OWG Date March 25 2 011 Sheet 1 of S Page 9 of 9
27. ty requirements for electrical equipments The DAB 84 card is CE compliant if all wires connected to all digital and analogue inputs and outputs and to the supply input are shorter than 3 meters 3 yd and 3 37 in 1 1 Communication Modes The DAB 84 card may be used to realise a telemetering telecontrol network both in Point to Point and Point to Multipoint modes The operating communication mode is selected by the Identification Address set into the card If this address is equal to 0 the unit works in Point to Point Mode while every address from 1 to 31 allows the Point to Multipoint Mode The address is set using the switches from 5 to 1 of the Dipswitches bank as explained in the 5 2 1 The Master Expansion Jumper on the right side of the box configure the unit as Master if single or as Expansion if connected to a Master unit The jumper configuration is explained in the 5 1 1 1 1 Point to Point communication Setting the Identification Address 0 the unit works in Point to Point mode In this case the network consists in two units one for each point Both local and remote units must be configured as Master and to avoid collisions during the communication in one of these the automatic repetition must be disabled as explained in the 5 2 2 If used the Expansion units must be in the same number in each side of the system In this operating mode a message exchange between the units is present to allow the mutual update of the o
28. utputs in according with the related inputs level The message length is of maximum 26 Bytes if all expansion cards are present The communication beginning may be originated by a status change in anyone of the digital inputs by the periodic repetition or by both of them The Analogue Inputs cannot begin a communication so if the DAB 84 cards are used to measure only analogue parameters a periodic repetition must be activated In a normal operating condition each sending causes an answer from the remote unit that must be correctly received within a suitable timeout and in its absence the sending card comes into in a repetition procedure until a correct Page 2 of 9 ERE S n c DAB 84 Instruction Manual Revision 3 0 answer is detected after which it returns in the normal operating condition The communication beginning from a status change is the condition to obtain the minimum number of transmissions but may be not adequate to transfer the analog parameters therefore the better communication system is the periodic repetition that may be configured with cycles from 1 second to 1 hour as shown in the Table 8 of the 5 2 2 In this operating mode at the supply switch on or after a manual reset the card waits 2 seconds to stabilise the analog sensors after which sends the first communication This moment is the initial time of the periodic repetition counter If a correct answer is received from the remote unit the system will remain idle u
Download Pdf Manuals
Related Search