AI - A Line of Fixed Port Active Hubs for ARCNET Local Area Networks

AI - A Line of Fixed Port Active Hubs for ARCNET Local Area Networks
AI
A Line of Fixed Port Active Hubs for ARCNET®
Local Area Networks
User Manual
#TD675100-0MG
Trademarks
Contemporary Controls, ARC Control, ARC DETECT and EXTENDA-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.
TD675100-0MG0000 Revised 3-2-04
Copyright
© Copyright January 1997-2004 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
Sovereign Court Two
University of Warwick Science Park
Sir William Lyons Road
Coventry CV4 7EZ 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 Control Systems, Inc. to notify any person of such
revision or change.
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Contents
Chapter 1 Introduction ........................................................ 1
1.1
Description ................................................ 1
1.2
Features .................................................... 2
1.3
Specifications ............................................ 3
1.4
Ordering Information ................................ 5
Chapter 2 Installation ........................................................... 7
2.1
Introduction ............................................... 7
2.2
Electromagnetic Compliance .................... 7
2.3
Mounting the AI ........................................ 8
2.4
Powering the AI ....................................... 8
2.5
Topologies ............................................... 11
2.6
Connecting Cables to the AI ................... 12
2.7
Variable Data Rates ................................ 21
2.8
Supporting Extended Timeouts ................ 22
Chapter 3 Operation .......................................................... 25
3.1
Theory of Operation ................................ 25
3.2
LED Indicators ........................................ 26
3.3
Isolating Faulty Nodes with Line
Activity Indicators................................... 28
Chapter 4 Service ............................................................... 29
Warranty ............................................................. 29
Technical Support ............................................... 30
Warranty Repair ................................................. 30
Non-Warranty Repair ......................................... 31
Returning Products for Repair ............................ 31
Appendices
Appendix A–Permissible Segment Lengths ........ 33
Appendix B–Declaration of Conformity ............. 36
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List of Figures
Figure 2-1 DC Powered ........................................................ 9
Figure 2-2 Redundant DC Powered .................................... 9
Figure 2-3 AC Powered ..................................................... 10
Figure 2-4 AC Powered with Grounded Secondary .......... 10
Figure 2-5 AC Powered with Battery Backup .................. 11
Figure 2-6 Repeater ........................................................... 11
Figure 2-7 Link ................................................................... 12
Figure 2-8 Hub ................................................................... 12
Figure 2-9 DC Coupled EIA-485 Option (-485) ................ 16
Figure 2-10 Each -485 Hub Port Has Provisions For
Applying Bias and Termination ......................... 17
Figure 2-11 AC Coupled EIA-485 Option (-485X) .............. 19
Figure 2-12 RJ-11 Connections Found on CC’s NIMs ........ 19
Figure 2-13 AI Twisted-Pair Pinouts ................................... 20
Figure 2-14 Front Panel of the AI2 and AI3 ........................ 20
Figure 2-15 RJ-45 Connector Pin Assignments ................... 21
Figure 2-16 Data Rate Switch ............................................. 22
Figure 2-17 Extended Timeout Jumpers ............................... 23
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1
Introduction
1.1
Description
The ARCNET Interconnect (AI) series of external fixed port
hubs provide a low cost method of expanding ARCNET local
area networks. Expansion methods include the use of repeaters,
links and hubs. Repeaters are used to extend a wiring segment
using the same cabling technology. A link allows the mixing of
two cabling technologies within one segment. A hub allows for
the addition of a segment and support for distributed star
topologies. The AI can implement all three expansion methods
depending upon the number of ports on the AI. The AI2
provides two ports for repeater and link applications while the
AI3 implements the hub function. However, the AI2 and AI3
utilize the same robust hub timing electronics found in
Contemporary Controls’ (CC’s) MOD HUB series of modular
active hubs. This includes precision delay line timing, digitally
controlled timers for dependable operation and reduced bit jitter.
The AI operates from either low voltage AC or DC power. For
DC operation, a voltage source in the range of 10 to 36 volts is
required. For AC operation, a voltage source in the range of 8 to
24 volts is required. Companion regulatory approved
transformers are available under separate model numbers for
UL and CE Mark applications.
The timing electronics 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. The AI series supports variable data rates
from 78 kbps to 10 Mbps in order to accommodate newer
ARCNET controller chips and popular EIA-485 transceivers.
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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 a
plant. Active links and repeaters provide extensions to bus
systems or bridging to other cable media.
1.2
Features
•
Compatible with the baseband ARCNET network
•
Compatible with all CC’s network interface modules
(NIMs) and active hubs
•
Supports either 2 or 3 ports
•
Panel-mount enclosure
•
Configurations available for either link, repeater or hub
operation
•
Supports coaxial, twisted-pair and fiber optic cable
•
LED indicator identifies reconfiguration of the network
•
Minimizes bit jitter with precision delay line timing
•
Watchdog timer prevents hub lockup
•
Hub unlatch delay digitally controlled
•
Low voltage AC or DC powered
•
Provisions for redundant power supplies
•
Supports variable data rates from 78 kbps to 10 Mbps
•
Accommodates AC or DC coupled EIA-485 networks
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1.3
Specifications
Electrical
Input voltage:
Input power:
Input frequency:
DC
10-36 volts
4 watts
N/A
AC
8-24 volts
4 VA
47-63 Hz
Mechanical
Optical Power Budget (25°C)
Fiber Size
(Microns)
-FOG
850 nm
(dB)
50/125
62.5/125
100/140
6.6
10.4
15.9
Environmental
Operating temperature:
0°C to +60°C
Storage temperature: –40°C to +85°C
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Functional
The data rate switch is not present on the -CXS, -CXB and
-TPB models.
Compliance:
ANSI/ATA 878.1
Extended timeouts:
Supports all three extended
ARCNET timeouts
Hub, Repeaters and
Link delay:
Unlatch delay time:
LED indicators:
320 ns maximum @ 2.5 Mbps
5.9 µs @ 2.5 Mbps
RECON–yellow
ACTIVITY–green
STATUS–green
Regulatory Compliance
CE Mark
FCC Part 15 Class A
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1.4
Ordering Information
The AI series is available in several configurations depending upon
the application and cable media supported.
Repeaters
AI2-CXB
AI2-TPB
AI2-485
AI2-485X
Coaxial bus repeater
Twisted-pair bus repeater
DC coupled EI-485 repeater
AC coupled EIA-485 repeater
Links
AI2-CXB/FOG-ST
AI2-TPB/FOG-ST
AI2-485/FOG-ST
AI2-485X/FOG-ST
Coaxial bus to fiber optic link
Twisted-pair bus to fiber optic link
DC EIA-485 to fiber optic link
AC EIA-485 to fiber optic link
Hubs
AI3-CXS
AI3-TB5
AI3-485
AI3-485X
AI3-485/FOG-ST
AI3-485X/FOG-ST
AI3-FOG-ST/TB5
AI3-FOG-ST/CXB
AI3-FOG-ST/485
AI3-FOG-ST/485X
Coaxial star hub
Twisted-pair bus hub
DC coupled EIA-485 hub
AC coupled EIA-485 hub
DC coupled EIA-485 to fiber hub
AC coupled EIA-485 to fiber hub
Twisted-pair bus/fiber backbone hub
Coaxial bus/fiber backbone hub
DC Coupled EIA-485/fiber backbone hub
AC Coupled EIA-485/fiber backbone hub
Accessories
AI-XFMR
AI-XFMR-E
AI-DIN
BNC-T
BNC-TER
Wall-mount transformer 120 Vac (nom)
Wall-mount transformer 230 Vac (nom)
DIN-rail mounting kit
BNC “T” connector
93 ohm BNC terminator
Contact factory regarding special requirements.
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2
Installation
2.1
Introduction
The AI series is intended to be panel mounted into an industrial
enclosure or into a wiring closet. Two #8 pan head screws (not
provided) are required for mounting. Optionally, a DIN rail
mount can be achieved by purchasing a DIN rail mounting kit.
2.2
Electromagnetic Compliance
The AI series complies with Class A radiated and conducted
emissions as defined by FCC part 15 and EN55022. This
equipment is intended for use in nonresidential areas. Refer to
the following notices in regard to 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 FCC 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. In a
domestic environment this product may cause radio
interference in which case the user may be required to take
adequate measures.
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The AI has been tested to EN50082 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 A - 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
reconfigurations occur. Normal operation resumed after
offending signal removed.
Class C - Complete loss of function. Unit resets and normal
operation restored without human intervention.
At no time did the AI 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
Mounting the AI
The AI is intended for mounting onto a vertical panel within an
industrial control enclosure. Two #8 screws can be used for
mounting the AI in a vertical orientation. Refer to the
mechanical specifications for details.
If it is desirable to mount the AI onto a DIN rail, an optional
DIN rail mounting clip (AI-DIN) must be purchased and
installed on the rear of the AI. Once the clip is mounted to the
AI, the AI can be snapped onto the DIN rail.
2.4
Powering the AI
The AI requires either low voltage AC or DC power in order to
operate. Consult the specifications for power requirements.
Power is provided to a four pin removable keyed connector and
there are several methods for providing power.
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2.4.1
DC Powered
Make connections as shown in the diagram. The AI
incorporates a DC-DC converter that accepts a wide voltage
range (10-36 Vdc) and converts the voltage for internal use.
Input current varies with input voltage so it is important to size
the power conductors accordingly. Input power to the AI does
not exceed 4 watts; therefore, at 10 Vdc, the input current is
approximately 400 ma. The ground connection to the AI is
connected to chassis within the AI. The input connections are
reverse voltage protected.
Figure 2-1. DC Powered
2.4.2
Redundant DC Powered
Redundant diode isolated DC power inputs are provided on the
AI for those applications where there is a concern that the AI
remain operational in the event of a primary power failure.
Make connections as shown in the diagram. Each power supply
source must be sized for the full 4 watt load of the AI. Do not
assume that input currents will be balanced from the two
supplies.
Figure 2-2. Redundant DC Powered
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2.4.3
AC Powered
If only AC power is available, the AI can be powered by the
secondary of a low voltage transformer whose primary is
connected to the AC mains. The secondary voltage must be in
the range of 8 to 24 Vac with the capability of delivering up to
4 VA of apparent power. The secondary of the transformer
must not be grounded. When using a grounded secondary
transformer refer to Figure 2-4. For convenience two auxiliary
power supplies are available. The AI-XFMR is intended for
120 Vac primary power while the AI-XFMR-E is intended for
230 Vac.
Figure 2-3. AC Powered
Figure 2-4. AC Powered with Grounded Secondary
2.4.4
AC Powered with Battery Backup
The AI can also be powered from both an AC and DC power
source. Usually the DC source is from a battery supply which is
connected as the DC powered option. Refer to the diagram for
details. In this application, the AI does not charge the battery so
separate provisions are required for charging. If the AC source
fails, the AI will operate from the battery source.
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Figure 2-5. AC Powered with Battery Backup
2.5
Topologies
Depending upon the number of ports on the AI, the AI can be
used as either a repeater, link or hub. The AI2 has only two
ports and, therefore, can be used as a repeater or link while the
AI3 has three ports and can be used as a hub.
2.5.1
Repeater
The repeater extends wiring segments of the same type of cable.
Coaxial cable or twisted-pair segments can be extended using
repeaters.
Figure 2-6. Repeater
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2.5.2
Link
A link converts one type of cabling segment into another. Using
two AIs in a link application, either a coaxial or twisted-pair
segment can be converted into a fiber segment.
Figure 2-7. Link
2.5.3
Hub
With a three port AI, the hub (or star topology) configuration
can be implemented. AI3s can also be cascaded in order to
create a distributed star topology.
Figure 2-8. Hub
2.6
Connecting Cables to the AI
The AI provides either two or three ports preconfigured for
either coaxial, twisted-pair or fiber optic cable. More
information on designing an ARCNET cabling system can be
found in CC’s publication “ARCNET Tutorial 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).
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2.6.1
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 AI ports. This cable will work, but
communication distances are reduced compared to RG-62/u
because of the higher attenuation of 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 port accommodates. When
connecting to a -CXS port, do not apply a terminator or BNC
“T” connector to the port. Simply connect the coaxial cable to
the BNC port.
2.6.2 Connecting Coaxial Cable Bus Networks (-CXB)
Some AI2 link and repeater models support coaxial bus
transceivers (-CXB) which allows the insertion of an AI at any
point within a bus segment. Usually, RG-62/u coaxial cable is
used to connect the various nodes and the AI requiring 93 ohms
of passive termination at the extreme ends of the bus segment.
This is accomplished using a BNC terminator (BNC-TER) and
BNC “T” connector (BNC-T) at each end. A BNC “T”
connector is then used to interconnect the various devices
within the segment. Make sure that all devices are -CXB
compliant.
If a bus segment is to be connected to a coaxial star port
(-CXS), connect the -CXS port only at the extreme ends of the
bus segment without a passive terminator. The -CXS port
effectively terminates the bus segment without the need for
additional termination.
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2.6.3 Connecting Twisted-Pair Bus Networks (-TPB)
Some AI2 link and repeater models have twisted-pair
transceivers (-TPB) which allows the insertion of an AI at any
point within a bus segment. Usually IBM type 3 unshielded
twisted-pair cable is (UTP) used, although shielded cable can
be used as well. A removable 5-position screw connector is
used to make connections. The middle pin is reserved for the
shield connection while phases A and B are available on each
of two pins to facilitate daisy-chain connections (within a bus
segment) or to attach a passive termination (at the end
devices). End devices require a passive terminator that matches
the impedance of the cable (typically 100 ohms).
2.6.4 Connecting Fiber Optic Cable (-FOG)
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. Bayonet style ST connectors, similar in operation to
BNC coaxial cable connectors, are provided for making the
fiber connections.
Fiber optic connections require a duplex cable arrangement.
Two unidirectional cable paths provide the duplex link. There
are two devices on the AI fiber port. One device, colored light
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. However, remember that to connect point A
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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.
2.6.5
Connecting DC Coupled EIA-485 Networks (-485)
A removable 5-position screw connector is provided for each
DC coupled EIA-485 segment. Two connections are provided
for each differential signal phases A and B. The middle pin
connects to a 100 ohm resistor referenced to DC common. 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 intact. All phase A signals on the AI network interface
modules and other hubs must be connected together. The same
applies to phase B. Figure 2-6 has been provided to assist in
connecting the various devices. If shielded cable is to be used,
the shielded end can be terminated to the middle pin on the
connector.
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 the EIA-485
daughterboard adjacent to the port connector. 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 connect an
external resistor across phase A and phase B.
Failsafe 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 +5V line while
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the other is tied to ground. Each resistor has a jumper
associated with it. If the two jumpers are installed, the resistor
tied to +5V is connected to the phase A signal line while the
grounded resistor is connected to the phase B line. This voltage
drop will bias the differential receivers into a defined state
when no differential drivers are enabled. Differential receivers
typically 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 E1
on the daughterboard. This is to be done for only the AI 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 AI
port is located at the extreme ends of the segment, install all
three jumpers at location E1 on the daughterboard. If the NIM
is located between the two end NIMs or AI ports, remove all
three jumpers. If external termination is desired, remove the
middle jumper at E1 and provide the external termination.
Figure 2-9. DC Coupled EIA-485 Option (-485)
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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
AIs and computers (pin SH has been provided for such a
connection on the AI) or by relying upon the third wire ground
of the power connector assuming that the DC power return is
connected to chassis ground on all computers (this is the case
with the AI). 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.
+5V
+5V
Rb
Rb
A
A
PIP2
PIP2
TXEN
TXEN
Rt
Rt
B
RXIN
Rb
B
Rb
Vcm
SH
RXIN
SH
Figure 2-10. Each -485 hub port has provisions for
applying bias and termination. Make sure common mode
voltage (Vcm) does not exceed +/–7 Vdc.
In summary, segments of -485 (-485D) connected NIMs can be
extended through the use of active hubs. Select an AI model
with a -485 compatible port. Connect one end of the segment to
this port following the same termination rules as used for a
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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.
2.6.6
Connecting AC Coupled EIA-485 Networks (-485X)
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 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 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) and the node count is higher with DC. The
AC coupled transceiver will only operate between 1.25 Mbps
and 10 Mbps.
The cabling rules of the -485X are similar to the -485. Wire a
maximum of 13 NIMs (reduce by one for each AI port) in a
daisy-chain fashion leaving the end devices as either NIMs or
AI ports. On these NIMs or AI ports insert a jumper at E1 on
both -485X daughterboards to invoke 120 ohm termination
resistors or leave the jumpers open and connect an external
terminating resistor to phases A and B. Termination should not
be applied to any of the NIMs located between the two end
NIMs or AI ports of the segment. Mixing -485 and -485D can
be accomplished by invoking backplane mode on -485 NIMs
and non-backplane mode on -485D NIMs.
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However, -485 or -485D NIMs cannot be mixed with -485X
NIMs together on one segment since signal encoding is
different.
Figure 2-11. AC Coupled EIA-485 Option (-485X)
WIRING CHART
RJ-11 CONNECTOR
PIN -TPS
1
2
3
4
5
6
N/C
LINE
LINE
N/C
-TPB
-485
-485X
N/C
LINE
LINE
N/C
N/C
LINE
LINE
N/C
N/C
LINE
LINE
N/C
Figure 2-12. RJ-11 Connections Found on CC’s NIMs
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PIN
-TPB
A
B
SH
A
B
LINE
LINE
SHIELD
LINE
LINE
-485
-485X
LINE
LINE
SHIELD
LINE
LINE
LINE
LINE
SHIELD
LINE
LINE
Figure 2-13. AI Twisted-Pair Pinouts
NOTE: For -TPB transceiver, LINE+ is defined at the leading
positive phase of the dipulse signal. For -485 transceiver,
LINE+ is defined as the pin with the more positive applied
failsafe bias. The -485X transceiver is not polarized.
Figure 2-14. Front Panel of the AI2 (left) and AI3 (right)
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2.6.7
Connecting Shielded Twisted-Pair Bus Networks via
RJ-45 Connectors (-TB5)
Some AI3 models support twisted-pair bus operation via dual
connectors. This allows insertion of the AI at any location on
the bus segment and provides continuous shielding between
devices. When the TB5 port is located at the end of a bus
segment, passive termination is required at the unused jack to
match the cable impedance (typically 100 ohms). Refer to
Figure 2-15 for the RJ-45 connector pin assignments.
18
27
36
45
54
63
72
81
Figure 2-15. RJ-45 Connector Pin Assignments
2.7
Variable Data Rates
Newer ARCNET controller chips support variable data rates up
to 10 Mbps. However, transceivers such as -CXS, -CXB and
-TPB will only operate at 2.5 Mbps. On these AI models there
are no provisions for variable data rates as evidenced by the
lack of a data rate switch. On all other models, a data rate
switch is present which must be set to the correct speed of the
network. A table has been provided to aid in setting the 8
position switch. Switch positions are labeled 0-7 with position 6
further identified by a dot indicating the 2.5 Mbps default
position. A clockwise rotation increases the data rate setting.
Use the following table to set the data rate:
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Figure 2-16. Data Rate Switch
NOTE: On -485X models data rates less than 1.25 Mbps are
not supported.
2.8
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 AI will work with
either 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 AI to accommodate
extended timeouts. On the board is jumper setting E1. The
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 available
setting is marked ET1, the next longest is ET2 and the longest is
ET3. Simply move the jumper to the desired position. With
newer ARCNET controller chips, the reconfiguration timers are
programmable and there may be no appropriate timeout setting.
To disable the RECON light, remove any jumpers from NORM,
ET1, ET2 or ET3.
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Figure 2-17. Extended Timeout Jumpers
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3
Operation
3.1
Theory of Operation
3.1.1
AI States
When the AI 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 AI
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 AI times the absence of an ARCNET logic
“1.” Once the unlatch delay time is exceeded (typically 5.9 µs
when operating at 2.5 Mbps), the AI reverts back to the IDLE
state.
3.1.2
Signal Regeneration
To generate an ARCNET signal requires the synthesis of signals
P1 and P2. These 100 ns non-overlapping pulses (when
operating at 2.5 Mbps) in turn drive the various transceivers on
each of the ports. 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.
EIA-485 ports incorporate a return to zero (RZ) signaling
scheme with a logic “1” signal equivalent to the logical OR of
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P1 and P2. These ports accommodate this signal generation
while maintaining compatibility with coaxial and fiber optic
signals.
3.1.3
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 µs (at standard timeouts and at 2.5 Mbps). 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. Newer ARCNET controller chips allow for
adjustable reconfiguration timers beyond the original standards.
These settings could confuse the RECON LED. To disable the
RECON LED, simply remove any jumper attached to the four
timeout positions.
3.1.4
Watchdog Timer
If no hub activity is sensed after a predetermined time, a
watchdog timer will automatically reset the AI timing
electronics. This is to ensure that the AI reestablishes
communication after a significant electrostatic or
electromagnetic phenomenon without requiring any human
intervention.
3.2
LED Indicators
There are several LED indicators on the AI that aid in
determining if the network is operating correctly. The indicators
are as follows:
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ACTIVITY Each port on the AI has an associated LED
indicator that indicates that ARCNET traffic is being received
on that port. The intensity of the LED will increase somewhat
with traffic. Transmitted data from that port is not indicated by
the ACTIVITY light. Therefore, disconnected cables, open
cables or cables attached to disabled ARCNET controller chips
will not light the ACTIVITY LED.
STATUS
With power applied and with no network cables
connected to the AI or if no valid ARCNET activity is present
on any one port on the AI, this indicator will flash at a periodic
rate indicating that the AI is functioning but idle. If ARCNET
activity is present and the internal regeneration of the ARCNET
signal is proper, this indicator will light, telling you that the AI
is receiving ARCNET signals and (faithfully) reproducing these
signals to other ports on the AI. If this indicator does not light
when activity is present on any hub port, as it should, then the
AI 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 AI, 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.
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3.3
Isolating Faulty Nodes with Line Activity
Indicators
The AI has port activity indicators. Each port activity indicator
lights whenever the corresponding port on the AI 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 port activity indicator
that corresponds to the port on the AI connected to the
chattering node will light brightly while all other port activity
indicators will appear dim. Disconnecting this cable from the AI
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.
Port activity indicators can also point out other problems with
the network. For example, port activity indicators light up when
the AI is on and each ARCNET compatible device that is
connected to the AI is on. If a port activity indicator is not on
for a device that is properly connected to the AI, then disconnect
the cable from the port and reconnect the cable to a similar
vacant port. If the indicator on the other port does not light
when the cable is connected, check the cable, the computer or
the network interface module for possible problems.
If the port activity indicator goes on when the cable is plugged
into another port, then the problem probably lies with the
original port on the AI.
If an AI port has a line activity indicator that is on but no cable
is attached to the connector, then the port is defective and the AI
should be returned. Contact our Customer Service department.
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4
Service
Warranty
Contemporary Controls (CC) warrants its product to the
original purchaser for one year from the product’s shipping
date. If a CC product fails to operate in compliance with its
specification during this 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. This warranty
does not cover repair of products that have been damaged by
abuse, accident, disaster, misuse, or incorrect installation.
CC’s limited warranty covers products only as delivered. User
modification may void the warranty if the product is damaged
during installation of the modifications, in which case this
warranty does not cover repair or replacement.
This warranty in no way warrants suitability of the product for
any specific application.
IN NO EVENT WILL CC 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, INCLUDING THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR PARTICULAR
PURPOSE OR USE, TITLE AND NONINFRINGEMENT.
TD675100-0MG
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Repair or replacement as provided above shall be the
purchaser’s sole and exclusive remedy and CC’s exclusive
liability for any breach of warranty.
Technical Support
Contemporary Controls (U.S.A.) will provide technical support
on its products by calling 1-630-963-7070 each weekday
(except holidays) between 8:00 a.m. and 5:00 p.m. Central time.
Contemporary Controls Ltd (U.K.) will provide technical
support on its products by calling +44 (0)24 7641 3786 each
weekday (except holidays) between 8:00 a.m. and 5:00 p.m.
United Kingdom time. If you have a problem outside these
hours, leave a voice-mail message in the CC after hours
mailbox after calling our main phone number. You can also fax
your request by calling 1-630-963-0109 (U.S.) or
+44 (0)24 7641 3923 (U.K.), or contact us via e-mail at
info@ccontrols.com or info@ccontrols.co.uk. You can visit our
web site at www.ccontrols.com. When contacting us, please
leave a detailed description of the problem. We will contact you
by phone the next business day or in the manner your
instructions indicate. We will attempt to resolve the problem
over the phone. If unresolvable, the customer will be given an
RMA number in order that the product may be returned to CC
for repair.
Warranty Repair
Products under warranty that were not subjected to misuse or
abuse will be repaired at no charge to the customer. The
customer, however, pays for shipping the product back to CC
while CC pays for the return shipment to the customer. CC
normally ships ground. International shipments may take
longer. If the product has been determined to be misused or
abused, CC will provide the customer with a quotation for
repair. No work will be done without customer approval.
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Non-Warranty Repair
CC provides a repair service for all its products. Repair
charges are based upon a fixed fee basis depending upon the
complexity of the product. Therefore, Customer Service can
provide a quotation on the repair cost at the time a Returned
Material Authorization (RMA) is requested. Customers pay the
cost of shipping the defective product to CC and will be
invoiced for the return shipment to their facility. No repair will
be performed without customer approval. If a product is
determined to be unrepairable, the customer will be asked if the
product can be replaced with a refurbished product (assuming
one is available). Under no circumstances will CC replace a
defective product without customer approval. Allow ten
working days for repairs.
Returning Products for Repair
To schedule service for a product, please call CC Customer
Service support directly at 1-630-963-7070 (U.S.) or
+44 (0)24 7641 3786 (U.K.). Have the product model and
serial number available, along with a description of the
problem. A Customer Service representative will record the
appropriate information and issue, via fax, an RMA number—a
code number by which we track the product while it is being
processed. Once you have received the RMA number, follow
the instructions of the Customer Service support representative
and return the product to us, freight prepaid, with the RMA
number clearly marked on the exterior of the package. If
possible, reuse the original shipping containers and packaging.
In any event, be sure you follow good ESD-control practices
when handling the product, and ensure that antistatic bags and
packing materials with adequate padding and shock-absorbing
properties are used. CC is not responsible for any damage
incurred from improper packaging. Shipments should be
insured for your protection.
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Ship the product, freight prepaid, to the location from which it
was purchased:
Contemporary Control Systems, Inc.
2431 Curtiss Street
Downers Grove, IL 60515
U.S.A.
Contemporary Controls Ltd
Sovereign Court Two
University of Warwick Science Park
Sir William Lyons Road
Coventry CV4 7EZ
U.K.
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Appendices
Appendix A—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
case 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
EIA-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.
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Appendix A (continued)
Table A-1. Permissible Cable Length and Nodes Per Segment
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Appendix B—Declaration of Conformity
Applied Council Directives:
Electromagnetic Compatibility Directive, 89/336/EEC Council
Directive as amended by Council Directive 92/31/EEC &
Council Directive 93/68/EEC
General Product Safety Directive 92/59/EEC
Standard to which Conformity is Declared
EN 55022:1995 CISPR22: 1993, Class A, Limits and Methods
of Measurement of Radio Disturbance Characteristics of
Information Technology Equipment
EN 50082-2:1995, Electromagnetic Compatibility - Generic
Immunity Standard, Part 2: Industrial Environment
Manufacturer:
Contemporary Control Systems, Inc.
2431 Curtiss Street
Downers Grove, IL 60515 USA
Authorized Representative:
Contemporary Controls Ltd
Sovereign Court Two
University of Warwick Science Park
Sir William Lyons Road
Coventry CV4 7EZ
UNITED KINGDOM
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Type of Equipment:
Industrial local area network repeater, link or hub
Directive
EMC
Model
AI2-CXB
AI2-TB5
AI2-485
AI2-485X
AI2-CXS/FOG-ST
AI2-TPB/FOG-ST
AI2-485/FOG-ST
AI2-485X/FOG-ST
AI3-CXS
AI3-TB5
AI3-485
AI3-485X
AI3-485/FOG-ST
AI3-485X/FOG-ST
AI3-FOG-ST/TB5
AI3-FOG-ST/CXB
AI3-FOG-ST/485
AI3-FOG-ST/485X
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
I, the undersigned, hereby declare that the products specified
above conform to the listed directives and standards.
George M. Thomas, President
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February, 2004
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