Contemporary Control Systems PC10420 User Manual

PC10420

ARCNET® Network Interface Modules for PC/104 Bus Computers

INST ALLA TION GUIDE

INTRODUCTION

The PC10420 series of ARCNET network interface modules (NIMs) links
PC/104 compatible computers with the ARCNET local area network (LAN).

ARCNET is classified as a token-bus LAN operating at a nominal 2.5 Mbps
while supporting 255 nodes. Interfacing ARCNET to a host computer
usually requires a NIM which plugs into the host computer’s bus.

The PC10420 incorporates the newer COM20020 ARCNET controller chip
with enhanced features over the earlier generation ARCNET chips. New
performance and integration enhancements include command chaining
operation and an internal 2K x 8 RAM buffer. There is no requirement for
wait-state arbitration.

Each PC10420 module has two LEDs on the board. The green LED
indicates that the module is receiving data on the network and the yellow
LED indicates bus access to the module. The PC10420 also has a piano
style DIP switch so that node addresses can be easily reassigned without
removing the module.

There are several versions of the PC10420 ARCNET NIM. The
PC10420-CXS supports coaxial star configurations requiring external
active or passive hubs. The PC10420-CXB supports coaxial bus
configuration usually requiring no hubs. Other versions include the
PC10420-FOG which supports fiber optic cable with either ST or SMA
connectors. The PC10420-TPB supports twisted-pair bus cabling using
RJ-11 and screw terminal connectors. There are various versions that
support EIA-485 communication each using RJ-11 and screw terminal
connectors.

On some models, operation up to 5.0 Mbps is possible. These models are
identified with a /5 designation.

SPECIFICATIONS

Environmental

Operating temperature: 0°C to +60°C
Storage temperature: –40°C to +85°C

Data Rates

PC10420* 2.5 Mbps, 1.25 Mbps, 625 kbps, 312.5 kbps, 156.25 kbps
PC10420/5* 5.0 Mbps, 2.5 Mbps, 1.25 Mbps, 625 kbps, 312.5 kbps

* The -CXS, -CXB and -TPB models can only operate at 2.5 Mbps.

The -485X model can only operate at 1.25, 2.5 or 5.0 Mbps.

Dimensions

3.550" x 3.775"
(90 mm x 95 mm)

Shipping Weight

1 lb. (.45 kg)

I/O Mapping

Supports I/O Mapping on any 16-byte boundary

Interrupt Lines

Supports strapping of IRQ 2/9, 3, 4, 5, 6, or 7

Compatibility

PC10420 series NIMs are compliant with ANSI/ATA 878.1 and PC/104

Specification 2.3.

Regulatory Compliance

FCC Part 15 Class A

Power Requirements

Model +5V –12V

PC10420-CXS 200 mA 20 mA
PC10420-CXB 200 mA 50 mA
PC10420-FOG-SMA 300 mA N/A
PC10420-FOG-ST 300 mA N/A
PC10420-TPB 200 mA 50 mA
PC10420-485 200 mA N/A
PC10420-485D 200 mA N/A
PC10420-485X 200 mA N/A
PC10420/5-485 200 mA N/A
PC10420/5-485D 200 mA N/A
PC10420/5-485X 200 mA N/A
PC10420/5-FG-ST 300 mA N/A

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INSTALLATION
Passive P2 Connector

Although the PC10420 is an eight-bit module, the PC10420 does provide a
P2 connector used for 16-bit applications. The advantage of the P2
connector is that 8-bit modules, such as the PC10420, can be located in the
middle of the PC/104 stack without compromising the integrity of the 16-bit
bus. Signals from the PC10420 are not connected to the passive P2
connector.

Mounting the PC10420

The PC10420 incorporates stack-through connectors and is shipped with
four 0.6" standoffs to facilitate mounting of the PC10420 onto the PC/104
stack. The PC10420 should be mounted below the 8-bit modules if any are
present in the system. If another eight-bit module is to be mounted above
the PC10420, use the enclosed standoffs. On some older eight-bit modules,
only two mounting holes are provided so only two standoffs are used. If
the PC10420 is the last module on the stack, use either two or four
M3x0.5-5MM panhead screws (not provided) to complete the mounting
onto the stack. Once mounted, field connections can be made.

Since the PC/104 stack does not make provision for a chassis (earth)
connection, a metal screw terminal has been provided for this purpose.
Simply connect one end of a green earthing wire to the screw terminal and
the other end to a suitable chassis ground.

Register Map

The PC10420 requires 16 contiguous I/O address locations in order to
access the COM20020 register and node ID switch. Because several
locations are reserved, it is important not to address another device to these
locations. The register map is shown in Table 1.

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I/O Read Write
Address Register Register

Base + 0 Status Interrupt Mark
Base + 1 Diagnostic Status Command
Base + 2 Address Pointer High Address Pointer High
Base + 3 Address Pointer Low Address Pointer Low
Base + 4 Data Data
Base + 5 Reserved Reserved
Base + 6 Configuration Configuration

Base + 7 Test ID/..../Next ID Test ID/..../Next ID

Base + 8 Node ID Switch Reserved
Base + 9 Node ID Switch Reserved
Base + A Reserved Reserved
Base + B Reserved Reserved
Base + C Reserved Reserved
Base + D Reserved Reserved
Base + E Reserved Reserved
Base + F Reserved Reserved

Table 1—Register Map

I/O Base Addressing

The I/O base address for the register map can be set with jumpers. The
PC10420 does not require any memory address space—simplifying
installation. See Table 2 for details.

A9 A8 A7 A6 A 5 A4 I/O ADDRESS

n nnnn 100
nnnn 110
nnn n 120
nnn 130
nn nn 140
nn n 150
nn n 160
nn 170
n nnn 180
nnn 190
nnn1A0
nn 1B0
nnn1C0
nn1D0
nn1E0

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A9 A8 A7 A6 A5 A4 I/O ADDRESS

n 1F0

nnnnn 200
nn n n 210
nn n n 220
nn n 230
nn n n 240
nn n 250
nn n 260
nn 270
n nnn 280
nnn 290
nn n 2A0
nn 2B0
nnn2C0
nn 2D0
nn2E0
n 2F0

nnnn 300* Default
nn n 310
nn n 320
nn 330
nnn 340
nn 350
nn360
n 370

nnn 380
nn 390
nn 3A0
n 3B0

nn 3C0
n 3D0

n 3E0

3F0

Key: n = Install Jumper

Table 2—I/O Base Address

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Interrupts

Interrupts can be invoked at jumper location E1 which consists of a series of
rows of two posts each. Each row is labeled with an interrupt line
corresponding to one of the PC bus interrupt designators. To enable an
interrupt, insert a jumper across a pair of posts corresponding to the desired
interrupt. Only one interrupt can be selected; therefore, only one jumper is
supplied. If no interrupts are desired, remove all jumpers at E1. The default
interrupt setting is INT 2.

Indicator Lights

There is a dual LED located at the PC10420 front plane. The yellow LED
indicates that the PC10420 is being accessed via its I/O address. The green
LED indicates that the PC10420 is receiving ARCNET traffic from the
network.

Node ID Switch

Although not always necessary with the COM20020, the PC10420 provides
a separate input port that reads an 8-bit DIP switch (SW1) located near the
board edge. This switch is intended to serve as a node ID switch, although it
can serve as a general purpose switch if desired. The node ID switch has no
connection to the COM20020 ARCNET controller chip.

The most significant bit (MSB) is switch position 1, and the least significant
bit (LSB) is switch position 8. A switch in the open position (off position or
away from the printed circuit board) introduces a logic “1.” Figure 1 shows
the node ID switch. In this example, the switch is set to hexadecimal
address F5.

MSB LSB

Figure 1—Node ID Switch

FIELD CONNECTIONS

The PC10420 is available in several transceiver options. Each transceiver,
which is matched to a particular cable type, is identified by a three-character
suffix appended to the model numbers. The capabilities of each transceiver
differs.

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-CXS Coaxial Star

In a coaxial star system, NIMs and hubs are interconnected in a point-to­point fashion using coaxial cable. A NIM can connect to one other NIM or
can connect to an unused port on a hub. Hub-to-hub connections are
allowed.

In a two-node system, simply connect the two -CXS NIMs together using
RG-62/u coaxial cable. The length of cable cannot exceed 2000 feet.

If more than two NIMs are used on a network, either an active or passive
hub is required. With passive hubs, a maximum of four NIMs can be
interconnected. Unused ports on the passive hub must be terminated with a
93-ohm (nominal) resistor. The maximum length between a passive hub port
and a NIM is 100 feet.

Active hubs provide overall better performance than passive hubs since
greater distances can be achieved along with a degree of isolation. Connect
each NIM to a port on the hub using RG-62/u coaxial cable. This length of
cable cannot exceed 2000 feet nor can the length of cable between two
cascaded hubs exceed 2000 feet. However, up to ten hubs can be cascaded
thereby providing an overall cable length of 22,000 feet. Unused ports on
active hubs need not be terminated.

Figure 2—Active hubs can be cascaded

for greater distances.

-CXB Coaxial Bus

For hubless systems, the -CXB transceiver can be used. NIMs are
interconnected with RG-62/u cables and BNC Tee connectors. Each -CXB
NIM represents a high impedance connection in both the powered and
unpowered states. Therefore, passive termination must be applied to both
ends of a bus segment. Use BNC style 93-ohm (nominal) resistors at each
end. The maximum segment length is 1000 feet and the maximum number
of NIMs that can be connected to a segment is eight.

To extend a bus segment beyond 1000 feet, an active hub is required. If the
hub port is of the -CXS type, connection can be made if a few simple rules
are followed. Only connect this bus segment at the end of a segment. Do not
connect the hub to the middle of a segment since the hub port is not of the

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high impedance type. Do not terminate the end which attaches to the hub
port since a -CXS port effectively terminates the end of a bus segment.
Simply remove the BNC Tee connector and terminator from the segment end
and attach the cable directly to the hub port. The opposite segment end still
requires termination if no hub connection is being made.

Figure 3—Bus segments can be extended

through active hubs.

-FOG Fiber Optic (-ST, -SMA)

The fiber optic option is designated -FOG; however, a further designation is
required in order to specify the type of
connector. The -FOG-ST uses the ST
style connector while the -FOG-SMA
uses the SMA style connector. Cable
sizes of 50, 62.5 or 100 micron duplex
cable can be used with either
connector.

Fiber optic connections require a
duplex cable arrangement. Only star
and distributed star topologies are
supported. Two unidirectional cable
paths provide the duplex link. There
are two devices on each NIM. 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 NIM and
another NIM or a hub to a NIM, 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.

Figure 4—Fiber Optic

Option (-FOG)

Optical Power Budget

The optical power budget is
the ratio of the light source

Table 3—The power budget varies with

the fiber core size.

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strength divided by the light receiver sensitivity expressed in dB. The link
loss budget, which includes losses due to cable and connectors, must be less
than the power budget. Assuming cable attenuation of 3.5 dB/km, up to
2 km of 62.5 µm fiber optic cable can be used per segment.

-TPB Twisted-Pair Bus

The -CXB transceiver can be modified to drive a balanced cable system
with the addition of some parts. This configuration is called -TPB and it
supports shielded or unshielded twisted-pair cable such as Category 5. Dual
RJ-11 connectors replace the single BNC connector in order to support the
popular modular plug connectors. For convenience, a three-position screw

terminal connector is also provided (see Figure 7). Follow the connector pin
assignments in Tables 4 and 5 when using these connectors or when mixing

cable types. Wiring between NIMs is accomplished in a daisy-chain fashion
with point-to-point cables connecting the various NIMs to create a bus
segment. The end NIMs will have one vacant RJ-11 socket which is to hold
the RJ-11 style 100-ohm terminator required to terminate the end points of
the bus segment. When terminating the screw terminal connector, install a
100 ohm, 1/4 watt resistor across terminals 1 and 2. Use twisted-pair cable
and observe polarity. Modular plugs must be installed on this cable so that
they do not invert the signals. Most satin cable does not twist the pairs nor
maintain signal polarity. Do not use this cable. To test for the proper cable
connections, hold both ends of the cable side by side with the retaining clips
facing the same direction. The color of the wire in the right-most position of
each plug must be the same if there is no inversion of the cable. If this is not
the case, the cable is inverted. Up to eight -TPB NIMs can be connected to
one segment which cannot exceed 400 feet in length.

The overall distance of a twisted-pair network can be expanded beyond 400
feet if hubs are used. Use a hub port that supports the same -TPB interface.

Figure 5—TPB NIMs are connected in a daisy-chain fashion

with terminators inserted at both end NIMs.

-485D DC Coupled EIA-485 (Non Backplane Mode)

The PC10420-485D supports DC coupled EIA-485 communication via a
daughter board which replaces the coaxial hybrid transceiver. This daughter
board receives the conventional P1 and P2 pulses intended for the coaxial
hybrid transceiver and converts them to an elongated P1 pulse (the width is
equal to P1 and P2) suitable for the EIA-485 differential driver. Therefore,

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do not set the COM20020 to backplane mode for EIA­485 communication as recommended in SMSC’s
application note and data sheet since Contemporary
Controls (CC) implements the same signaling on this
daughter board. With our approach, the same software
driver used for coaxial networks will function
with the EIA-485 version of the PC10420 without
modification.

Figure 6—Modular Jack

Numbering Orientation

Modular Connector Pin

Assignments

6-Contacts

Pin Usage

1 Not Available
2 Not Used
3 Line+
4 Line
5 Not Used
6 Not Available

–

Table 4—Modular

Connector Pin

Assignments for -TPB

Figure 7) and two RJ-11 connectors are

supplied on each NIM and are bussed together
to provide a convenient daisy-chain method for
connecting multiple nodes onto one segment.
This segment can be up to 900 feet long of
Category 5 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. Pin 3 of the modular jack on
each NIM must be connected together. The same
applies to pin 4. Most modular (satin cable)
telephone wiring inverts the phase of the wiring,
thereby 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. Refer to
Tables 4 and 5 for connector pin assignments.

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 daughter board. With the middle jumper inserted at location

E1 on the daughter board, 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 terminator in the unused RJ-11 modular jack or install a 120
ohm, 1/4 watt resistor across pins 1 and 2 on the screw terminal connector.

One three-position screw terminal (see

Table 5—Screw Terminal Connector

Pin Assignments for -485, -485D -485X and -TPB

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Incorporating a resistance value less than 120 ohms is not recommended
since it may excessively load the EIA-485 transceivers.

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 daughter board. 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 V is
connected to the (+) signal line while the grounded resistor is connected to
the (–) line. This voltage drop will bias the differential receivers into the
“1” 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 daughter board.
This is to be done for only the two NIMs
located at the end of the segment. All other
NIMs will have their jumpers removed.

The termination and bias rules are simple. If the NIM 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, remove all
three jumpers. If external termination is desired, remove the middle jumper
at E1.

Figure 7—Screw

Terminal Connector

Numbering Orientation

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 PC computers or by relying upon the third wire ground of the
power connector assuming that the DC power return is connected to chassis
ground on the PC computer. Another approach would be to connect the DC
common of each PC 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. A ground connection can be
found at pin 3 of the screw terminal connector.

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Segments of -485D connected NIMs can be extended through the use of
active hubs. Select a MOD HUB expansion module with a -485D
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.

-485 DC Coupled EIA-485 (Backplane Mode)

If the software driver you intend to use sets the COM20020 into backplane

mode, you will need the PC10420-485

Jumper

E3/E4 # of Nodes

1-2, 3-4, 5-6 2-5

3-4, 5-6 6-15

5-6 16-30

Table 6—Backplane Mode,

DC Coupled EIA-485

Option (-485)

place a jumper at E5 on pins 1 and 2. If termination is not required, simply
move the E5 jumper to pins 2 and 3. Cabling and expansion rules are the
same for the -485 and -485D options.

version. This version does not utilize the
daughter-board approach. Instead you
will find three sets of jumpers labeled

E3, E4 and E5 which replace the three

jumper functionality of E1 found in the

-485D model. Operation is similar to
that of the -485D version but the bias is
distributed among all the nodes. If bias
is required, place jumpers in locations
E3 and E4 according to Table 6. The
jumper configuration of E3 must match
that of E4. If termination is required,

Note: When all jumpers are left open, minimal bias is provided by a pair of
10K-ohm resistors.

-485X AC Coupled EIA-485

The AC coupled EIA-485 transceiver offers advantages over 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). The AC coupled
transceiver will operate at 1.25, 2.5 and 5.0 Mbps while the DC coupled
transceiver will operate over all six data rates.

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The cabling rules of the -485X are similar to the -485D. Dual RJ-11
connectors and one three-position screw terminal connector are used in each
NIM. Wire a maximum of 13 NIMs in a daisy-chain fashion leaving the end
NIMs with vacant RJ-11 connections. On these NIMs insert a jumper at E1
on both -485X daughter boards to invoke 120-ohm termination resistors or
leave the jumpers open and insert RJ-11 style passive terminators in each of
the two vacant RJ-11 jacks. Termination can also be accomplished by
installing a 120-ohm, ¼ watt resistor across pins 1 and 2 of the screw
terminals at each end of the bus segment. Refer to Tables 4 and 5 for
connector pin assignments. Termination should not be applied to any of the
NIMs located between the two end NIMs of the segment. Do not mix -485D
and -485X NIMs together on one segment; however, bridging of the
technologies is possible using active hubs with the appropriate transceivers.
To extend -485X segments, use a hub as discussed under the -485D section.
Make sure that the active hub transceivers are of the -485X type. Cable
inversion is not of any consequence.

Figure 8—Jumper settings for EIA-485 models.

Electromagnetic Compatibility

The PC10420 series complies with Class A radiated and conducted
emissions as defined by FCC Part 15 and EN55022. This equipment is
intended for use in non-residential areas.

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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NEED MORE HELP INSTALLING THIS PRODUCT?

More information can be found on our web site at www.ccontrols.com. When
contacting one of our offices, just ask for Technical Support.

Warranty

Contemporary Controls (CC) warrants its new product to the original purch­aser 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, mis­use, 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 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.

Returning Products for Repair

Return the product to the location from which 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

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