Mod Hub User Manual - Contemporary Controls
Contents
1. A Figure 2 3 AC Coupled EIA 485 Option 485X TD401600 0MO 15 WIRING CHART RJ 11 CONNECTOR 123456 2 6 Turning the Active HUB Turn the MOD HUB unit on by depressing the Power switch located on the lower right of the MOD HUB s front panel Note Once your MOD HUB is on we recommend that it be left on unless you are installing removing modules to from the MOD HUB Connecting disconnecting cables with the hub on will cause no damage to the MOD HUB 1 BNC Connector 7 Timing Indicator 2 Port Activity Indicator 8 RJ 11 Connector 3 Timing Module 9 ST or SMA Connector 4 Reconfiguration Indicator 10 Power Switch 5 Power Supply 11 Fuse Box Indicator for Pwr 12 Power Cord Receptacle 6 Power Supply Indicator for Pwr Figure 2 4 Front Panel of the MOD HUB Shown Fully Loaded TD401600 0MO 16 2 7 Ensuring Proper HUB Operation Check each port s line activity indicator All indicators on the front panel of the active hub should light up when the hub is turned on assuming the cables connected to the hub are also connected at the other end to ARCNET network interface modules or active hubs Please note that the RECON indicator in the right most location on the front panel will only flash for a second when th2. 8 1 54 8 L 3 00 5 MODHUB 16F 16EF 76mm SIDE VIEW 15 52 394mm 12 0 14 75 304mm 374mm 6 1400 152mm 355 1 13 28mm E 12 0 HE 9 50 304mm 2 241mm H MODHUB 16F N SIDE VIEW TD401600 0MO 3 14 Regulatory Compliance UL 1950 listed cUL listed per CSA 22 2 No 950 95 IEC 950 classified CFR 47 Part 15 Class A CE Mark 1 5 Power Requirements Electrical MODHUB 16 series MODHUB 48 series Input voltage 100 VAC to 230 VAC 100 VAC to 230 VAC 10 10 Input current 0 5 amps max 1 0 amps max Input frequency 47 Hz to 63 Hz 47 Hz to 63 Hz Input fuse s 1 amp slo blo 1 amp slo blo 5 mm x 20 mm 5 mm x 20 mm 1 6 Ordering Information Select an adequately sized MOD HUB for the number of ports required The MODHUB 16 has four slots and can support to 16 ports The MODHUB 48 has twelve slots and can support up to 48 ports EXP expansion modules generally support four ports each and are ordered separately Refer to EXP data sheets for detailed information MOD HUB E designation means export model and is shipped with a continental Europe power cord These units have two input fuses to address unpolarized power systems and carry the CE Mark This model can be modified at the factory for single fuse operation if requested MOD HUB designation means flange mounted enclosure which is standa
3. and the internal regeneration of the ARCNET signal is proper this indicator will light telling you that the MOD HUB is receiving ARCNET signals and faithfully reproducing these TD401600 0MO 18 signals to other ports on the MOD HUB If this indicator does not light when activity is present on any hub port as it should then the timing module is defective RECON Reconfigurations of the network routinely occur as nodes are added to the network and pose no problem to the network When they occur this LED will flash on for one second to facilitate viewing even though the reconfiguration process takes a fraction of a second However frequent reconfigurations can degrade performance of the network as indicated by this LED flashing repeatedly or lighting continuously If this is occurring on your MOD HUB you need to isolate the connected computers to find out which node is causing these reconfigurations The cause of frequent reconfigurations could be a faulty network interface module defective cable duplicate node IDs or a high incidence of electrical interference An occasional flash of this light is normal as automatic reconfigurations are a feature of ARCNET If this is all that is viewed you can feel well assured that the network is operating properly 2 9 Isolating Faulty Nodes with Line Activity Indicators In addition to the four indicators on the timing module each port on each expansion module has a line activity ind
4. Control Systems Inc to notify any person of such revision or change TD401600 0MO i Contents Chapter 1 Chapter 2 Chapter 3 Chapter 4 1 11 DeScription 1 1 2 Benefits 2 1 3 5 2 1 4 Regulatory 4 1 5 4 1 6 Ordering Information 4 Installation 6 21 6 2 2 Electromagnetic 6 23 Flange Mounting 7 24 Rack Mounting Kit 7 2 5 Connecting Cables to the MOD HUB 8 2 6 Turning the Active HUB 16 2 7 Ensuring Proper HUB Operation 17 2 8 Troubleshooting Tips 17 2 9 Isolating Faulty Nodes with Line Activity Indi atotS ucescem 19 2 10 Supporting Extended Timeouts 20 22 3 1 Theory 22 SIGE 24 Technical SUPpoOrt 24 Watranty 24
5. MOD HUB timing module This is to ensure that the hub reestablishes communication after a significant electrostatic or electromagnetic phenomenon without requiring any human intervention TD401600 0MO 23 4 Service More comprehensive information is on our web site at www ccontrols com This includes technical manuals and other documents When contacting one of our offices just ask for Technical Support Warranty Contemporary Controls CC warrants its new product to the original purch aser for two years from the product shipping date Product returned to CC for repair is warranted for one year from the date that the repaired product is shipped back to the purchaser or for the remainder of the original warranty period whichever is longer If a CC product fails to operate in compliance with its specification during the warranty period CC will at its option repair or replace the product at no charge The customer is however responsible for shipping the product CC assumes no responsibility for the product until it is received CC s limited warranty covers products only as delivered and does not cover repair of products that have been damaged by abuse accident disaster mis use or incorrect installation User modification may void the warranty if the product is damaged by the modification in which case this warranty does not cover repair or replacement This warranty in no way warrants suitability of the product for any
6. Returning Product for 24 Declaration of 24 TD401600 0MO Appendix Permissible Segment Lengths 25 List of Figures Figure 2 1 485 13 Figure 2 2 Each 485 hub port has provisions for applying bias and termination Make sure common mode voltage Vcm does not x 14 Figure 2 3 AC Coupled 485 Option 485 15 Figure 2 4 Front Panel of the MOD HUB Shown Pully Loaded 16 Figure 2 5 extended timeout settings only affect the RECON light with no affect to the hub OPCTAlIOMN tected 21 TD401600 0MO iii 1 Introduction 1 1 Description The MOD HUB series of modular active hubs provides a convenient and flexible method of expanding ARCNET local area networks EXP expansion modules are installed into the MOD HUB that support the particular cabling technology desired The MOD HUB is available with either four expansion slots or twelve Since most expansion modules support four ports each a total of 48 ports can be provided within one hub MOD HUBs can be cascaded via an expansion port on each hub to expand the network to the limit of the ARCNET technology The MOD HUB is provided with an integral universal voltage power supply four o
7. isolated by a pulse transformer Unlike the DC coupled EIA 485 wiring polarity is unimportant Either inverted or straight through cable can be used or even mixed within one AC coupled network Much higher common mode voltage levels can be achieved with TD401600 0MO 14 AC coupling due to the transformer coupling which has a 1000 Vdc breakdown rating There are disadvantages to the AC coupled transceiver as compared to the DC coupled technology The DC coupled distances are longer 900 feet compared to the AC coupled distance 700 feet The cabling rules of the 485X are similar to the 485 Wire a maximum of 13 NIMs reduce by one for each hub port in daisy chain fashion leaving the end devices as either NIMs or hub ports On these NIMs or hub ports insert a jumper at 1 on both 485X daughterboards to invoke 120 ohm termination resistors or leave the jumpers open and insert RJ 11 style passive terminators In the case of a hub port an RJ 11 style tap is required Termination should not be applied to any of the NIMs located between the two end NIMs or hub ports of the segment Do not mix 485 485D and 485X NIMs together on one segment however bridging of the technologies is possible using two appropriate expansion ports on the MOD HUB To extend 485X segments use a hub as discussed under the 485 section Cable inversion is not of any consequence A E1 E1
8. power return is connected to chassis ground on all computers this is the case with the MOD HUB Another approach would be to connect the DC common of each computer to a cold water pipe Connected systems each with different elevated grounds can cause unreliable communications or damage to the EIA 485 differential drivers Therefore it is important that an adequate grounding method be implemented TD401600 0MO 13 1 2 Figure 2 2 Each 485 hub port has provisions for applying bias and termination Make sure common mode voltage Vcm does not exceed 7 Vdc Segments of 485 485D connected NIMs can be extended through the use of active hubs Select a MOD HUB expansion module with a 485 compatible port Connect one end of the segment to this port following the same termination rules as used for a NIM This hub port counts as one NIM when cable loading is being calculated The NIM electrically closest to the hub port should not have any termination or bias applied Follow the same rules for other segments attached to different hub ports Each hub effectively extends the segment another 900 feet Maintain the same cabling polarity as the NIMs by using cable connections that do not invert the signals 2 5 7 Connecting AC Coupled EIA 485 Networks The AC coupled EIA 485 transceiver offers advantages over the DC coupled EIA 485 No bias adjustments need to be made since each transceiver has its own fixed bias network
9. star IBM Type 3 RJ 11 TPB twisted pair bus IBM Type 3 RJ 11 485 DC coupled EIA 485 IBM Type 3 RJ 11 485X AC coupled EIA 485 Type 3 11 1 This represents the minimum distance between two nodes between a node and a hub 5 May require a jumper change on the EXP to achieve this distance Table 1 Permissible Cable Length and Nodes Per Segment TD401600 0MO 26 Cable Length Max Nodes Min Max Bus Segment Notes 0 2000 ft 610 m N A 5 5 dB 1000 ft max 0 1500 ft 457 m N A 7 0 dB 1000 ft max 6 ft 2 m 1000 ft 305 m 8 5 5 dB 1000 ft max 0 3000 ft 915 N A 4 3 dB km max 0 6000 ft 1825 m N A 4 3 4 max 0 9000 ft 2740 m N A 4 0 dB km max 02 46000 14000 N A 0 5 dB km max 32800 ft 10000 N A 1 5 dB km max 0 35000 ft 10670 m N A 1 5 dB km max 0 330 ft 100 m N A uses internal BALUNs 6 ft 2 m 400 ft 122 m 8 0 900 ft 274 m 17 DC coupled 0 700 ft 213 m 13 transformer isolated TD401600 0MO 27 This page is deliberately left blank TD401600 0MO 28
10. A precision delay line gated oscillator forms the basis of the regeneration circuitry and was chosen because of the predictable delay experienced from this type of oscillator which is important in reducing bit jitter 485 expansion modules incorporate a non return to zero NRZ signalling scheme with a logic 1 signal equivalent to the logical OR of P1 and P2 The expansion modules TD401600 0MO 22 accommodate this signal generation while maintaining compatibility with coaxial and fiber optic signals Timers A simple crystal oscillator and divider are used to develop the unlatch delay time and reconfiguration timers Although not critical the unlatch delay timer is more repeatable from a crystal oscillator However the reconfiguration timer is more critical The reconfiguration timer does not sense a reconfiguration on the network it only predicts that a reconfiguration will occur This is accomplished by noting that no data has occurred for 82 us at standard timeouts Once this timer is exceeded the yellow RECON LED is lit for about 950 ms If the hub is operated on a network with extended ARCNET timeouts jumpers must be set on the timing module to extend the reconfiguration timer to match the network timeouts There are a total of four jumper settings corresponding to the four possible timeouts Watchdog Timer If no hub activity is sensed after a predetermined time a watchdog timer will automatically reset the
11. HUB when 19 equipment is stacked vertically with no voids Still it is important to check that the MOD HUB does not experience an increase in its ambient temperature that exceeds its specified rating of 60 C Ensure that there is adequate power service for the MOD HUB and that circuit overloading is not introduced with the addition of the MOD HUB This is especially important when power strips are used in mounting racks Make sure that earthing ground connection is maintained to the MOD HUB through any power strip 2 5 Connecting Cables to the MOD HUB The MOD HUB is shipped without EXP expansion modules Select the appropriate expansion modules for the cable type and distance desired Refer to the individual expansion module installation instructions for information on installing the modules More information on designing an ARCNET cabling system can be found in CC s publication ARCNET Tutorial amp Product Guide Attach the coaxial twisted pair or fiber optic cables to the devices that are being networked in the ARCNET LAN refer to Appendix A to verify that maximum cabling distance specifications are not exceeded 2 5 1 Connecting Coaxial Cable Star Networks CXS There are generally two types of coaxial cables that are used with ARCNET RG 59 u and RG 62 u RG 59 u is 75 ohm cable which does not precisely match the impedance of the transceivers used on the MOD HUB expansion modules This cable will work but communicat
12. MOD HUB Series A Line of Modular Active Hubs for ARCNET Local Area Networks User Manual TD401600 OMO CONTEMPORARY CONTROLS Trademarks Contemporary Controls ARC Control ARC DETECT and EXTEND A BUS are trademarks or registered trademarks of Contemporary Control Systems Inc ARCNET is a registered trademark of Datapoint Corporation Other product names may be trademarks or registered trademarks of their respective companies TD401600 OMO Revised November 2010 Copyright Copyright June 1996 2010 by Contemporary Control Systems Inc All rights reserved No part of this publication may be reproduced transmitted transcribed stored in a retrieval system or translated into any language or computer language in any form or by any means electronic mechanical magnetic optical chemical manual or otherwise without the prior written permission of Contemporary Control Systems Inc 2431 Curtiss Street Downers Grove Illinois 60515 USA Tel 1 630 963 7070 Fax 1 630 963 0109 E mail info ccontrols com WWW http www ccontrols com Contemporary Controls Ltd 14 Bow Court Fletchworth Gate Coventry 5 6SP UK Tel 44 0 24 7641 3786 Fax 44 0 24 7641 3923 E mail info ccontrols co uk Disclaimer Contemporary Control Systems Inc reserves the right to make changes in the specifications of the product described within this manual at any time without notice and without obligation of Contemporary
13. ase of hub to hub connections there is the possibility that no node exists on that segment The permissible cable length of a segment depends upon the transceiver used and the type of cable installed Table A 1 provides guidance on determining the constraints on cabling distances as well as the number of nodes allowed per bus segment The maximum segment distances are based upon nominal cable attenuation figures and worst case transceiver power budgets Assumptions are noted When approaching the maximum limits a link loss budget calculation is recommended When calculating the maximum number of nodes except 485 networks on a bus segment do not count the hub ports that terminate the bus segment as nodes However do consider the maximum length of the bus segment to include the cable attached to the hub ports Several bus transceivers require a minimum distance between nodes Adhere to this minimum since unreliable operation can occur TD401600 0MO 25 Appendix A continued Permissible Cable Lengths and Nodes Per Segment Trans ceiver Description Cable Connectors CXS coaxial star RG 62 u BNC CXS coaxial star RG 59 u BNC CXB coaxial bus RG 62 u BNC FOG duplex fiber optic 50 125 SMA or ST FOG duplex fiber optic 62 5 125 SMA or ST FOG duplex fiber optic 100 140 SMA or ST FG3 duplex fiber optic singlemode ST FG3 duplex fiber optic 50 125 ST FG3 duplex fiber optic 62 5 125 ST TPS twisted pair
14. e bus segment to TPS port without passive termination Do not attach a TPS port to the middle of the bus segment It will be necessary to invert the wiring sense at the TPS port since the TPS port has inverted polarity to a TPB port BALUNs introduce a signal inversion 2 5 5 Connecting Fiber Optic Cable FOG FG3 Single mode fiber optic cable is available in one size and multimode fiber optic cable is typically available in three sizes 50 125 62 5 125 and 100 140 The larger the size the more energy that can be launched and therefore the greater the distance Two connectors are supported the SMA and the ST The conventional SMA connector offers a threaded termination When this type of connection is tightened excessively the fiber optic cable can break resulting in unreliable communications Also the degree of tightening affects the optimum throughput of the cable Depending upon the degree of tightening fiber alignment can vary from the optimal coupling thereby introducing some attenuation The ST connector alleviates both of these problems but is generally more expensive than the SMA connector The ST provides a bayonet style connector similar in operation to a BNC coaxial cable connector TD401600 0MO 10 Fiber optic connections require a duplex cable arrangement Two unidirectional cable paths provide the duplex link There are two devices at each port on the MOD HUB expansion module One device colored li
15. e hub is powered on or when reconfigurations occur on the network The other three indicator lights located in line with the RECON indicator specifically the PWR PWR and TIMING indicators should always be lit when the hub is on and operating properly Additionally the activity indicator for each port should be lit if a cable is connected to that port and the device at the opposite end of the cable is on Refer to the next section covering troubleshooting tips if normal hub operation is not observed 28 Troubleshooting Tips If one of the devices in your ARCNET LAN loses its communications capabilities after the MOD HUB has been installed and used first check the four indicator lights on the timing module the right most module on the front panel of the MOD HUB unit Note Whenever any problems occur with the MOD HUB unit carefully document exactly what happened and what steps you took to handle the problem This will assist us in helping you solve the problem 2 8 1 Timing Module Indicators PWR This indicator should be lit when the MOD HUB is powered The internal positive DC power is continually monitored to verify that this voltage is within specification If this indicator is not lit when the hub is turned on there is a problem with the internal positive power supply TD401600 0MO 17 PWR This LED should also be lit when the MOD HUB is powered This LED monitors the internal negative DC power to ensure that it is opera
16. ght gray is the transmitter and the other dark gray is the receiver Remember that light goes out of the light gray To establish a working link between a hub and a network interface module or a hub to another hub the transmitter of point A must be connected to a receiver at point B Correspondingly the receiver at point A must be connected to a transmitter at point B This establishes the duplex link which is actually two simplex links Fiber optic cable is available paired for this purpose Usually the manufacturers labeling is only on one cable of the pair which is handy for identifying which of the two cables is which Establish your own protocol for connecting cable between hubs and NIMs in the field using the manufacturers labeling as a guide But remember that to connect point A to point B requires a paired fiber optic cable and that the light gray connector at one point must connect to a dark gray connector at the other point 2 5 6 Connecting DC Coupled EIA 485 Networks RJ 11 connector is provided for each DC coupled 485 segment This segment can be up to 900 feet long of IBM Type 3 unshielded twisted pair cable and as many as 17 nodes can occupy the segment Make sure that the phase integrity of the wiring remains in tact Pin 3 of the modular jack on each NIM and hub port must be connected together The same applies to pin 4 Most modular satin cable telephone wiring flips the phase of the wiring the
17. icator Each line activity indicator lights whenever the corresponding port on the MOD HUB receives ARCNET signals The intensity of these indicator lights changes with the amount of activity and this is how defective nodes can be isolated The worst possible occurrence is the chattering node A chattering node generates reconfigurations continuously as evidenced by the RECON light being continuously lit because this node has a defective receiver on its network interface module Under these circumstances the line activity indicator that corresponds to the port on the expansion module connected to the chattering node will light brightly while all other line activity indicators will appear dim Disconnecting this cable TD401600 0MO 19 from the MOD HUB will extinguish the RECON indicator and return all other port activity lights to equal brightness thereby isolating the defective node For large installations the time saved in identifying the problem can be immense Line activity indicators can also point out other problems with the network For example line activity indicators light up when the MOD HUB is on and each ARCNET compatible device that is connected to the MOD HUB is on If a line activity indicator is not on for a device that is properly connected to the MOD HUB then disconnect the cable from the connector and reconnect the cable to a similar vacant connector on another module If the indicator on the other module doe
18. igurations occur Normal operation resumed after offending signal removed Class Complete loss of function Unit resets and normal operation restored without human intervention At no time did the MOD HUB fail to return to normal operation or become unsafe during the execution of these tests A copy of the Declaration of Conformity is in the appendix 2 3 Flange Mounting The MODHUB 16 is also available in a flange mount MODHUB 16F for mounting to a panel board or subpanel Make sure the MODHUB 16F flanges are mounted onto a vertical surface to ensure proper airflow to the MOD HUB If desired the four mounting feet located at the bottom of the enclosure can be removed using a small screwdriver 24 Rack Mounting Kit Both the MODHUB 16 and MODHUB 48 can be installed in standard 19 racks using the MTG RAK rack mounting kit occupying 7 of vertical rack space Either one MODHUB 16 16E two MODHUB 16s 16Es side by side or one MODHUB 48 can be mounted using one rack mounting kit To install the MOD HUBs to the shelf provided with this kit simply remove the four rubber feet and attach the MOD HUB directly to the shelf using the screws from the rubber feet Be TD401600 0MO 7 careful that the complete rack does not become unstable due to the increased mechanical load The height of the MTG RAK exceeds the height of the MOD HUB to ensure that air flow will still be maintained through the MOD
19. ion distances are reduced compared to RG 62 u because of the higher attenuation of TD401600 0MO 8 RG 59 u cable We recommend RG 62 u because it is a better match to the transceivers and a full 2000 foot segment distance can be achieved using this cable Both cables support male BNC connectors which the CXS expansion module accommodates 2 5 2 Connecting Coaxial Cable Bus Networks There is no expansion module for a bus transceiver CXB however bus topology is supported with the MOD HUB Ina bus configuration one end of the segment terminates into a CXS expansion module without a passive terminator However the other end of the bus segment is terminated with a passive terminator Be sure to use the proper passive terminator 93 ohms for RG 62 u and 75 ohms for RG 59 u Do not attach the CXS expansion module in the middle of a bus segment using a BNC connector However the same effect can be accomplished by splitting the bus segment into two pieces each of which attaches to a CXS port Again no passive termination needs to be applied to the hub side of a bus segment 2 5 3 Connecting Twisted Pair Star Networks TPS Each TPS port is constructed as CXS port with an internal BALUN transformer A BALUN which is an acronym for BALanced UNbalanced connects the single ended CXS transceiver to a balanced transceiver suitable for driving balanced twisted pair cabling The internal BALUN in the TPS port
20. is compatible in wiring to an external MUX LAB s part number 10070 BALUN Therefore a TPS port can directly connect to another TPS port on either a hub or a NIM or connect to an external BALUN attached to a CXS port In both cases use straight through twisted pair cable with RJ 11 connectors Straight through cable provides a one to one correspondence in cable connections at both ends Straight through cable can be identified as follows Take both connectors from a cable length and lay them side by side with the locking clip facing the same direction The wire color present on the left most side of one connector must be the same color on the TD401600 0MO 9 left most side of the other connector This is a straight through cable which is used exclusively to connect TPS ports If the cable color on the left side of a connector appears on the right side of the other connector this inverted cable will result in operational problems with your twisted pair network 2 5 4 Connecting Twisted Pair Bus Networks TPB The TPS transceivers use internal BALUNs and therefore not directly compatible with twisted pair bus networks All TPS systems must be tied in either a star one hub and multiple NIMs or distributed star multiple hubs and multiple NIMs topology Under no circumstances should more than two TPS ports be connected to the same cable However a TPS port terminate the ends of a TPB network Connect one end of th
21. o the location of the installed equipment Note This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of the CFR Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense Warning This is a Class A product as defined in EN55022 domestic environment this product may cause radio interference in which case the user may be required to take adequate measures TD401600 0MO 6 The MOD HUB has been tested to 55024 Generic Immunity Standard Industrial Environment This standard identifies a series of tests requiring the equipment to perform to a particular level during or after the execution of the tests The three classes of performance are defined by CC as follows Class Normal operation however occasional reconfigurations may occur or throughput reduced due to error recovery algorithm by the ARCNET data link level protocol Class B Throughput reduced to zero and continuous reconf
22. ontrols CC network interface modules NIMs e Supports up to 48 ports in four port increments e Two sizes of enclosures 16 and 48 ports e Offers easy expansion with plug in modules e Mixes coaxial twisted pair and glass fiber optic cable in one hub e Isolates network faults with diagnostic LEDs e LED indicator identifies reconfiguration of the network e Minimizes hub jitter with precision delay line timing e Activity LEDs for each port e Provision for rack mounting e Watch dog timer prevents hub lockup e Hub unlatch delay digitally controlled 1 3 Specifications Mechanical See diagrams on page 3 TD401600 0MO 2 Operating temperature 0 C to 60 C Storage temperature 40 C to 85 C Functional Hub delay 320 ns typ Unlatch delay time 5 9 us typ Extended timeouts Supports all three extended ARCNET timeouts Signalling rate 2 5 Mbps nominal Compliance ANSI ATA 878 1 8 80 17 60 7 70 223mm 447mm 195mm 1 7 r HUB 6 00 4 16 16E MODHUB 48 48 SIDE VIEW 1043 2 264mm pi 8 66 953 219mm 242 mm
23. r sixteen slot card cage and internal timing module permanently installed into the hub s backplane There are no expansion modules provided with the MOD HUB The timing module uses a precision delay line timing generator which regenerates the incoming ARCNET signal without introducing excessive bit jitter The regenerated signal is then sent to all other ports on the hub A watchdog timer is included to prevent the possibility of hub lockup eliminating the necessity of cycling power on a failed hub The hub unlatch delay time is derived from a crystal oscillator for high accuracy and repeatability Active hubs increase the robustness of ARCNET networks They maximize the distance that can be achieved on each cable segment up to 2000 feet on coaxial segments They prevent interference to the network by squelching reflections caused by open or shorted cable segments attached to the hub Unused hub ports need not be terminated Active hubs allow for a distributed star topology thereby minimizing the cabling required in plant TD401600 0MO 1 There are several LED indicators that assist in troubleshooting the network One LED indicator informs if the network has undergone a reconfiguration Another indicator senses if the hub is properly generating internal hub signals There are separate LEDs that monitor the two internal power supplies 1 2 Benefits e Compatible with the baseband ARCNET network e Compatible with all Contemporary C
24. rd for panel board mounting For rack mounting do not specify the F designation but order a MTG RAK instead The MTG RAK supports either two MODHUB 16s 16Es or one MODHUB 48 TD401600 0MO 4 MODHUB 16F N designation means that a version of the MODHUB 16F with vented cover is installed into NEMA 1 enclosure A duplex receptacle is provided inside the NEMA 1 enclosure This receptacle must be wired via a conduit connection from an appropriate power source Model MODHUB 16 MODHUB 16E MODHUB 16F MODHUB 16EF MODHUB 16F N MODHUB 48 MODHUB 48E MTG RAK Description 16 pt powered card cage 120V 50 60 Hz 16 pt powered card cage 230V 50 60 Hz 16 pt powered card cage flange mounted 120V 50 60 Hz 16 pt powered card cage flange mounted 230V 50 60 Hz 16 pt powered card cage flange mounted NEMA 1 enclosure 120V 50 60 Hz 48 pt powered card cage 120V 50 60 Hz 48 pt powered card cage 230V 50 60 Hz MODHUB rack mounting kit TD401600 0MO 5 2 Installation 2 1 Introduction The MOD HUB can be either desktop mounted panel mounted or rack mounted One model the MODHUB 16F N has its own NEMA 1 enclosure for wall mounting 2 2 Electromagnetic Compliance The MOD HUB series complies with Class A radiated and conducted emissions as defined by CFR 47 Part 15 and EN55022 This equipment is intended for use in nonresidential areas Refer to the following notices in regard t
25. reby reversing the connections to pins 3 and 4 at each end Do not use this type of cable Some modular cable is not even twisted Be sure to use the proper cable TD401600 0MO 11 Termination Each end of the segment must be terminated in the characteristic impedance of the cable A 120 ohm resistor can be invoked with a jumper which resides on EIA 485 daughterboard adjacent to the RJ 11 connector on the expansion module With the middle jumper inserted at location E1 on the daughterboard 120 ohms of resistance is applied across the twisted pair With the jumper removed no termination is applied If it is desired to apply external termination instead remove this jumper and insert an RJ 11 style tap not provided and terminator in the RJ 11 port Bias In addition to the termination it is also necessary to apply bias to the twisted pair network so that when the line is floated differential receivers will not assume an invalid logic state There are two precision bias resistors Rb of equal value on each daughterboard One resistor is tied to the 5 V line while the other is tied to ground Each resistor has a jumper associated with it If the two jumpers are installed the resistor tied to 5 is connected to the signal line while the grounded resistor is connected to the line This voltage drop will bias the differential receivers into a defined state when no differential drivers are enabled Differential receivers t
26. s not light when the cable is connected check the cable the computer or the network interface module for possible problems If the line activity indicator goes on when the cable is plugged into another module then the problem probably lies with the original module If a hub port has a line activity indicator that is on but no cable is attached to the connector then the module is defective and should be returned Contact our Customer Service Department 2 10 Supporting Extended Timeouts Although seldom used ARCNET networks can be configured for extended timeouts to facilitate geographically larger networks In this situation each network interface module must be configured for the same timeout The MOD HUB will work with any of the four available timeout settings but the RECON indicator will function unreliably if the reconfiguration detection circuitry is not configured for the same timeout as the network There are four jumper settings on the timing module to accommodate extended timeouts With the power removed from the MOD HUB use a small star screwdriver to remove the timing module Along one edge of the module is jumper setting E1 A jumper can be found installed in the NORM position This is the factory setting and the default setting for standard ARCNET networks which is the shortest setting The next TD401600 0MO 20 available setting is marked ET1 the next longest is ET2 and the longest is ET3 Simply move the jumper
27. specific application INNO EVENT WILL BE LIABLE FOR ANY DAMAGES INCLUDING LOST PROFITS LOST SAVINGS OR OTHER INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PRODUCT EVEN IF CC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES OR FOR ANY CLAIM BY ANY PARTY OTHER THAN THE PURCHASER THE ABOVE WARRANTY IS IN LIEU OF ANY AND ALL OTHER WARRANTIES EXPRESSED OR IMPLIED OR STATUTORY INCLUD ING THE WARRANTIES OF MERCHANTABILITY FITNESS FOR PARTICULAR PURPOSE OR USE TITLE AND NONINFRINGEMENT Returning Products for Repair Return the product to the location where it was purchased by following the instructions at the URL below www ccontrols com rma htm Declaration of Conformity Information about the regulatory compliance of this product can be found at the URL below www ccontrols com compliance htm TD401600 0MO 24 Appendix Permissible Segment Lengths A segment is defined as any portion of the complete ARCNET cabling system isolated by one or more hub ports On a hubless or bus system the complete ARCNET cabling system consists of only one segment with several nodes however a system with hubs has potentially many segments An ARCNET node is defined as a device with an active ARCNET controller chip requiring an ARCNET device address Active and passive hubs do not utilize ARCNET addresses and therefore are not nodes Each segment generally supports one or more nodes but in the c
28. ting within an acceptable power range If this indicator is not lit when the hub is turned on there is a problem with the internal negative power supply If neither the PWR nor the PWR indicators light when the MOD HUB is turned on check for a blown fuse in the MOD HUB To open the fuse box on the front panel of the MOD HUB domestic models only Turn off the MOD HUB by depressing the power switch located on the right side of the front panel of the MOD HUB Unplug the power cord from the power receptacle on the front panel of the MOD HUB Locate the fuse box between the power switch and the power receptacle on the front panel of the hub Gently place the wide edge of a screwdriver beneath the fuse box cover and lift to dislodge the cover Lift out the fuse attached to the fuse box cover and check the fuse The fuse is blown if the wire in the fuse is broken If the fuse is blown replace it with the spare 5 mm x 20 mm fuse located in the fuse box cover and then close the fuse box reattach the power cord and turn on the MOD HUB If after replacing the fuse the PWR and PWR indicators still do not light up when the hub is turned on call technical support Note Export models do not have spare fuses Both fuses in the fuse holder are actively used TIMING If no cables are connected to the MOD HUB or if no valid ARCNET activity is present on any one port on the MOD HUB this indicator is off If ARCNET activity is present
29. to the desired position Figure 2 5 The extended timeout settings only affect the RECON light with no affect to the hub operation TD401600 0MO 21 3 Operation 3 1 Theory of Operation Hub States When the MOD HUB has installed expansion modules the timing module waits for the first instance of an ARCNET signal on any one of its ports During this time the hub is in IDLE mode with all port receivers enabled and all port transmitters disabled As soon as the first port senses an ARCNET signal there should only be one in a normally operating ARCNET system the hub enters the ACTIVE state with the receiving port left enabled and all other receivers disabled During this state all transmitters are enabled with the receiving port s transmitter disabled This allows all nodes on the network to hear a particular node which has momentary control of the network while squelching any echoes from unterminated lines open or shorted cables The hub remains in the ACTIVE mode until the last ARCNET signal is received by the originating port To determine if the last signal has been sent the hub times the absence of an ARCNET logic 1 Once the unlatch delay time is exceeded typically 5 9 ms the hub reverts back to the IDLE state Signal Regeneration To generate an ARCNET signal requires the synthesis of signals 1 and P2 These 100 ns non overlapping pulses in turn drive the various transceivers on each of the expansion modules
30. ypically switch at or near zero volts differential and are guaranteed to switch at 200 mV Through the transition point 70 mV of hysteresis will be experienced Therefore a positive bias of 200 mV or greater will ensure a defined state We recommend that bias be applied to both ends of the wiring segment by installing the two end jumpers located at position 1 on the daughterboard This is to be done for only the hub ports or NIMs located at the ends of the segment All other NIMs will have their jumpers removed The termination and bias rules are simple If the NIM or hub port is located at the extreme ends of the segment install all three jumpers at location 1 on the daughterboard If the NIM is located between the two end NIMs or hub ports remove all three jumpers If external termination is desired remove the middle jumper at E1 and provide the external termination TD401600 0MO 12 1 1 1 1 Figure 2 1 EIA 485 Daughterboards For EIA 485 DC operation it is very important that all devices on the wiring segment be referenced to the same ground potential in order that the common mode voltage requirement 7 Vdc of the EIA 485 specification is achieved This can be accomplished by running a separate ground wire between all hubs and computers or by relying upon the third wire ground of the power connector assuming that the DC
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