Рук_п_16ДуДк (1031887), страница 22
Текст из файла (страница 22)
The sum of these ASCIIcodes is 1A9h. The modulo-256(100h) - of 1A9h is A9h.ADAM-5000D-3How to Use the Checksum FeaturePrintable ASCII CharactersHEXD-4ASCIIHEXASCIIHEXASCII40@60`21!41A61a22"42B62b23#43C63c24$44D64d25%45E65e26&46F66f27'47G67g28(48H68h29)49I69i2A*4AJ6Aj2B+4BK6Bk2C,4CL6Cl2D-4DM6Dm2E.4EN6En2F/4FO6Fo30050P70p31151Q71q32252R72r33353S73s34454T74t35555U75u36656V76v37757W77w38858X78x39959Y79y3A:5AZ7Az3B;5B[7B{3C<5C]7C|3D=5D\7D}3E>5E^7E~3F?5F_ADAM-5000Appendix EEADAM-4000/5000System GroundingInstallationADAM-5000E-1ADAM-4000/5000 System Grounding InstallationE. 1 Power Supplies For relevant wiring issues,please refer to the following scheme :ERTAC Power LineMNFBTr3Isolation AC TransformerTo prevent system control from interferences caused by external powerNFB+P /S-DC10~30VAD AM 5000CP /S PI /OGNDU+VNFBConnect to AI/DI/DO modules (not for Relay output)The power sources for DI.
DO. and AI. should be independentP /SDC24VNFBDCOnly for Relay outputP /SDC24VACFan, Light...etc.E1 R1 T1Figure E-1: Grounding SchemeE.2Grounding InstallationØ The outer case for the module is made of iron and fitted with a fanand convection holes with filters.Ø If possible, wiring should be connected to the module through anexternal terminal block (T/B) to avoid external wires directly gettinginto the inside of the module. Its advantages are (1) a clear demarcation for external/internal wiring responsibility, (2) wire numberingcan be arranged in an explicit and concise manner, and (3) an easydiagnostics for the wiring problems and a more aesthetical layoutplan.E-2ADAM-5000Appendix EFAN (Outflowing)ADAM 5000/485T/BRelayFigure E-2: External Terminal Block and FanE.3External DI, DO, AI, AO Wiring ReferenceØ The common end of some D.I. and D.O. modules is connected withthe GND of ADAM-5000/4000 system.
Therefore, the common endof external DI and DO signal wiring should not be grounded withthose on-site machineries.Ø Within an environment that is subject to multiple interferences, it isadvised that a higher voltage level, e.g. a voltage above 12 VDC,should be used to ward off possible interferences.Ø The signal wire for AI and AO must be of a shielded type, i.e.
withsurrounding copper mesh and aluminum foil for proper shielding.For the specification of the signal wires, please refer to User’sManual.E.4Requirements for RS-485 signal wiresØ Use RS-485 twisted-pair as signal wire. The quality of signaltransmission can be improved in proportion with the number oftwists per foot of the wire. If the wire has more twists per foot, thesignal quality could be better.Ø Twisted -pair wire compliant with EIA-422 or EIA-485 standards,which contains 24AWG thin copper conductor with copper meshand aluminum foil for shielding.ADAM-5000E-3ADAM-4000/5000 System Grounding InstallationØ The shielding material of the wires should only be grounded onone end as illustrated in the following diagram. This is to avoidground loop.ADAM SystemOn-Site FacilitiesAIGroundingFigure E-3: Grounding for on-site facilities and ADAM-5000/4000SystemsØ Since shielded twisted-pair has been adopted for signal wires, onlyDATA+ and DATA- of ADAM-5000 system should be connected.And the shielding materials should be treated in the same manneras with AI and AO signal wires, i.e.
it should be connected toGround on only one end through the COM port on computer or onADAM-5000 system such as illustrated in the following diagram:PCDATA+DATA Gounded only on one endFigure E-4: Grounding for signal wiresE-4ADAM-5000Appendix EE.5 Grounding reference (Ground bar for the factoryenvironment should have a standard resistance below5 Ω)Since ADAM-4000 / 5000 system comes with a plastic outer case withDC power supply, its grounding procedure should be done accordingto the following points:Ø Power supply : The E terminal of the external power supply shouldbe connected with the panel.Ø The outer case of panel should be fixed with two grounding bus.Connect the ground of power (E-terminal) to the grounding buswith shortest path.
Use single contact for connection.Ø Another grounding bus is for connection with AI and AO shieldedsignal wires. While AI and AO signal wires enter inside the panel,the shielding materials is stripped off and its copper mesh shouldbe entangled together (There is no effect leaving alone any singlewire strand). Connect to grounding bus in the shortest path, andthen connect the two grounding buses in a way such as thefollowing illustration: (Please note that wire length should not betoo long, otherwise it will compromise the quality of the twistedpair wires)T/BAIADAM 5000/485AODCP/SEGrounding BusTrCopper mesh for Shielding(should be grounded only on one end)Grounding BusConnect to ground bar on the factory.The ground bar should have a resistance below 5 ohm.EFigure E-5 : Grounding ReferenceADAM-5000E-5ADAM-4000/5000 System Grounding InstallationE.6Some Suggestions on Wiring LayoutØ Since communication is carried through high-frequency signals, itis advisable that the wiring layout should be paid due attention to.Any wire should best remain as a single integral wire.
Nevertheless,if you should need another wire for extended connection, it issuggested that you use soldering iron to connect the disparatewires together. The parts of copper mesh should be solderedtogether too.Ø Generally, factories will layout the power lines, control lines, signallines and communication lines within separate conduits. Sincecommunication lines and signal lines are most susceptible tointerference, you should consider avoid laying them parallel withany power line in close distance.
Nevertheless, if they shouldremain parallel with the power line, just keep a proper distancebetween them. Basically, an AC current up to 2A should require adistance of 50 cm. The bigger the current or voltage, the longer thedistance is required.Ø For communication lines and AI/O signal lines, it is suggested thatthey should be carried within Zinc-gilded tube for crush resistance.Meanwhile, one end of the zinc-gilded tube should be connected tofactory facilities and grounded together.Ø While planning your wire layouts, you should consider layoutsthat can save wire length.E-6ADAM-5000Appendix FFGrounding ReferenceADAM-5000F-1Grounding ReferenceField Grounding and Shielding ApplicationOverviewUnfortunately, it’s impossible to finish the system integration task at atime.
We always meet some troubles in field. Such as communicationnetwork or system isn’t stable, noise influence, and equipment isdamaged or hungs up by thunders. However, the most possible issueis just the improper wiring; ie, grounding and shieldinF. As you knowthe 80/20 rule in our life: we spend 20% time for 80% works, but 80%time for left 20% works. So to system integration, we paid 20% cost forWire / Cable and 80% cost for Equipment.
However, 80% reliabilitydepends on Grounding and ShieldinF. In a word, we just need to pay20% investment and work on those two issues to get a high reliablesystem.This application note will bring you some concepts about fieldgrounding and shieldinF. Below topics will be illustrated in followingpages.1. Grounding1.1The ‘Earth’ for reference1.2The ‘Frame Ground’ and ‘Grounding Bar’1.3Normal Mode and Common Mode1.4Wire impedance1.5Single Point Grounding2. ShieldingF-22.1Cable Shield2.2System ShieldingADAM-5000Appendix F3.
Noise Reduction Techniques4. Check Point ListF.1Grounding1.1 The Earth for referenceWhy we think theEARTH as GROUND?As you know that the EARTH can t be conductive indeed.But those parallel resistors make the EARTH as a singlepoint and just for reference.Figure F-1: Think the EARTH as GROUND.• Why we think the EARTH as GROUND?As you know that the EARTH can not be conductive indeed. But allbuildings base on EARTH. Steels, concretion and relational cablessuch as Lighting Arrester and power system were connected toEARTH. Think them as resistors, then those infinite parallel resistorsmake the EARTH as a single point and just for reference.ADAM-5000F-3Grounding Reference1.2 The Frame Ground and Grounding BarNNNGSingle Phase, Three LineL110VN220V110VLGGGNeutral is the physical cable from Generator.Ground is the local physical cable that connected toGround Bar .Figure F-2: Grounding Bar.According to previous description, the grounding is the most important issue for our system.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
