SeaLevel SeaLINK plus 485I User manual

Part # 2104
SeaLINK+485I
USER MANUAL
TM
M
Sealevel Systems, Inc. Phone: [phone]
PO Box 830 Fax: [phone]
Liberty, SC 29657 USA www.sealevel.com

Contents
INTRODUCTION........................................................................ 1
INSTALLATION INSTRUCTIONS................................................ 2
WINDOWS 98/ME/2000/XP/VISTA™OPERATING SYSTEMS..........2
PHYSICAL INSTALLATION...............................................................3
CONFIGURATION ..................................................................... 7
ELECTRICAL INTERFACE SELECTION ..............................................7
SWITCH EXAMPLES.........................................................................8
TECHNICAL DESCRIPTION....................................................... 9
SPECIFICATIONS .................................................................... 10
APPENDIX A-TROUBLESHOOTING....................................... 11
APPENDIX B-HOW TO GET ASSISTANCE ............................ 12
APPENDIX C-ELECTRICAL INTERFACE............................... 13
APPENDIX D-GROUND LOOP PHENOMENON ...................... 14
APPENDIX E-ASYNCHRONOUS COMMUNICATIONS ............ 15
APPENDIX F-SILK-SCREEN.................................................. 16
APPENDIX G-COMPLIANCE NOTICES.................................. 17
WARRANTY............................................................................ 18
Figures
Figure 1- RS-422, 4 Wire RS-485 (Default).............................................8
Figure 2 - RS-485, 2 Wire with Echo........................................................8
Figure 3 - RS-485, 2 Wire No Echo..........................................................8
Figure 4 – SeaLINK+485I cabling example...........................................14
Figure 5 - Asynchronous Communications Bit Diagram .....................15
© Sealevel Systems, Inc.
SL9092 Revision 4/2007
Sealevel Systems, Incorporated. All rights reserved.

Introduction
Sealevel Systems SeaLINK+485I Page 1
Introduction
Overview
The Sealevel Systems SeaLINK+485I equips the PC with 1 isolated USB to
RS-422/485 Asynchronous serial port providing a versatile interface for
common RS-422/485 needs. The SeaLINK+485I connects through the PC’s
external USB port, so it does not require opening the computer case. Resources
such as IRQ’s and I/O addresses are also not utilized. It does require a system
that supports USB in hardware and operating system.
What’s Included
The SeaLINK+485I is shipped with the following items. If any of these items is
missing or damaged, contact the supplier.
•SeaLINK+485I Isolated USB to RS-422/485 Serial I/O Adapter
•USB Cable Part Number CA179 for Connecting to Upstream
Host/Hub
•Sealevel Software

Installation
Installation Instructions
Windows 98/ME/2000/XP/Vista™ Operating Systems
Do not connect the device to a USB port until the software is installed.
1. Start Windows.
2. Insert the Sealevel Software CD in to your CD drive.
3. If ‘Auto-Start’ is enabled the installation window will
automatically appear. Otherwise, navigate to the root directory of
your CD drive and double-click the ‘autorun.exe’ application to
launch the installation window.
4. Select ‘Install Software’.
5. Select the Part Number for your device from the listing.
6. The setup file will automatically detect the operating environment
and install the proper components. Follow the information
presented on the installation screens that follow.
7. A screen may appear with the declaration: “The publisher cannot
be determined due to the problems below: Authenticode signature
not found.” Please select the ‘Yes’ button and proceed with the
installation. This declaration simply means that the Operating
System is not aware of the driver being loaded. It will not cause
any harm to your system.
8. During setup, you may specify installation directories and other
preferred configurations. This program also adds entries to the
system registry that are necessary for specifying the operating
parameters for each driver. An uninstall option is included to
remove the driver and all registry/INI file entries from your
system.
9. Proceed with the physical installation of your SeaLINK USB serial
adapter.
NOTE:
Windows NT is not USB aware and thus cannot
support this device.
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Installation
Physical Installation
The screen captures below are taken from a Windows 98 installation. Your
particular operating system may differ slightly from what is shown based on
your version of windows.
The SeaLINK+485I can be connected to any Upstream Type “A” port either at
the PC host or an Upstream Hub. The SeaLINK+485I is hot-pluggable,
meaning there is no need to power down your computer prior to installation.
The SeaLINK+485I has an onboard 8 position dip switch that is used to
configure the interface. Prior to connecting the SeaLINK+485I, be sure to
configure this dip switch for your specific application. Please see the
Configuration section for more information. The SeaLINK+485I is defaulted to
RS-422 mode so changes are only required if you will be using the product in an
RS-485 application.
1. After installing the software connect SeaLINK+485I to an Upstream Host
or Hub.
This indicates that the system has recognized the new device and will now
proceed to locate a driver.
Sealevel Systems SeaLINK+485I Page 3

Installation
Sealevel Systems SeaLINK+485I Page 4
Since you have already installed the software by running “Setup”, simply click
“Next” to proceed. The drivers that were installed during setup will
automatically be used to configure the adapter for use.

Installation
Windows has now located a driver and installed the software. After the driver
has been located click “Finish. You should see one more “New Hardware
Found”, indicating the actual port being created. If you view your systems
Device Manager at this point, you should have a new “COM” port in the
Port(COM & LPT) Device Class. It should look similar to the screen shot on the
following page.
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Installation
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You can access your new COM: port by using the assigned COM: identifier
shown above. In this case, it is COM5: but this assignment will vary from
system to system. At this point, the hardware is recognized. To verify operation
use Sealevel Systems supplied WinSSD diagnostic utility. WinSSD can be
found in the Start menu under Programs, SeaCOM group.

Configuration
Sealevel Systems SeaLINK+485I Page 7
Configuration
Electrical Interface Selection
The port on the SeaLINK+485I has the ability to be used in both half and full
duplex RS-422/485 applications. This is selectable through DIP-switch SW1.
The chart below describes each of the switch position’s function. Please refer to
the following page for switch setting examples. Switch SW1, in the “ON”
position, either enables, adds or connects, based on the function of the switch
position listed below. Switch SW1, position OFF, disables, removes or
disconnects .
SW1 Function
1 RS-485 Two Wire Auto Enable/Disable
2 Echo Enable/Disable
3 Adds or removes the 120 ohm termination
4 Adds or removes the 1K ohm pull-up resistor in the
RS-422/RS-485 receiver circuit (Receive data only)
5 Adds or removes the 1K ohm pull-down resistor in the
RS-422/RS-485 receiver circuit (Receive data only)
6 Connects the TX+ to RX+ for RS-485 two wire operation
7 Connects the TX- to RX- for RS-485 two wire operation
8 Not Used

Configuration
Switch Examples
Please use the following examples to configure your adapter.
ON
12345678
OFF
RS-422
Figure 1- RS-422, 4 Wire RS-485 (Default)
OFF
ON
RS-485 12345678
OFF
Figure 2 - RS-485, 2 Wire with Echo
ON
RS-485 12345678
OFF
Figure 3 - RS-485, 2 Wire No Echo
Sealevel Systems SeaLINK+485I Page 8

Technical Description
Sealevel Systems SeaLINK+485I Page 9
Technical Description
The SeaLINK+485I: utilizes a USB UART. This chip features programmable
baud rate, data format, 128 byte Dual Port TX Buffer, and 384 byte Dual Port
RX Buffer. The RS-422/485 transceiver supports data rates up to 921.6K baud.
Features
•Hot-Pluggable device
•Does not require opening the case
•No system resources are required (i.e. I/O ports or IRQ’s)
•LED status indicators for “USB Enabled”, “TD”, and “RD”
Connector Pin Assignments (DB25 Male)
The SeaLINK+485I complies with the EIA-530 pin out with the following
signals supported
Signal Name Pin # Mode
GND Ground 7
RDB RX+ Receive Positive 16 Input
RDA RX- Receive Negative 3 Input
TDB TX+ Transmit Positive 14 Output
TDA TX- Transmit Negative 2 Output
Technical Note: The modem control signals are biased as follows : RTS is
connected to CTS, DTR is connected to DCD and DSR, and RI is tied
inactive.

Specifications
Sealevel Systems SeaLINK+485I Page 10
Specifications
Environmental Specifications
Specification Operating Storage
Temperature
Range 0º to 50º C
(32º to 122º F) -20º to 70º C (-4º to 158º F)
Humidity Range 10 to 90% R.H.
Non-Condensing 10 to 90% R.H. Non-Condensing
Manufacturing
•All Sealevel Systems Printed Circuit boards are built to UL 94V0 rating and
are 100% electrically tested. These printed circuit boards are solder mask
over bare copper or solder mask over tin nickel.
Power Consumption
Supply line +5 VDC
Rating 100 mA
Mean Time Between Failures (MTBF)
Greater than 150,000 hours. (Calculated)
Physical Dimensions
Package Length 3.8 inches (9.66 cm)
Package Width 2.3 inches (5.84 cm)
Package Height 1.0 inches (2.54 cm)

Appendix A – Troubleshooting
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Appendix A - Troubleshooting
Serial Utility test software is supplied with the Sealevel Systems adapter and
should be used in the troubleshooting procedures. Using this software and
following these steps, most common problems can be eliminated.
1. If your adapter isn’t working, first check to make sure that USB support is
enabled in the System BIOS and it is functioning properly in the operating
system. This can be done by using either the Windows 98/ME or Windows
2000 Device Manager.
2. Ensure that the Sealevel Systems software has been installed on the
machine so that the necessary files are in place to complete the installation.
3. When the SeaLINK+485I is configured properly, the USB Enabled LED
(EN) will be lit. This should allow you to use Sealevel’s WinSSD utility
and the supplied loopback plug to check communications. The supplied
loopback plug connects TD to RD. If you decide to test the Modem
Control Signals, a full pin loopback plug will be required. Details on
loopback plugs are included on WinSSD. Contact Sealevel Systems if you
need further assistance
4. When testing the SeaLINK+485I in loopback mode, you should see both
the TD and RD LED”s flashing as well as seeing echoed data on the screen.
The loopback test first transmits a HEX pattern, 55AA, and then an ASCII
string of data. If this test passes, then the SeaLINK+485I is ready for use in
your application.
5. Please note that if the card is configured for 2 wire RS-485 with no echo a
loopback test is not possible. The receiver in this case will be turned off and
the test will fail. If you plan on using this device in two wire mode test the
adapter in RS-422 mode first. Then configure the adapter for your
application.

Appendix B – How To Get Assistance
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Appendix B - How To Get Assistance
Please refer to
Appendix A - Troubleshooting prior to calling Technical Support.
1. Read this manual thoroughly before attempting to install the
adapter in your system.
2. When calling for technical assistance, please have your user
manual and current adapter settings ready. If possible, please have
the adapter connected in a computer ready to run diagnostic tests.
3. Please visit www.sealevel.com for the latest software updates and
manuals.
4. Technical support is available Monday through Friday from 8:00
a.m. to 5:00 p.m. Eastern time. Technical support can be reached at
[phone].
RETURN AUTHORIZATION MUST BE OBTAINED FROM
SEALEVEL SYSTEMS BEFORE RETURNED MERCHANDISE WILL
BE ACCEPTED. AUTHORIZATION CAN BE OBTAINED BY
CALLING SEALEVEL SYSTEMS AND REQUESTING A RETURN
MERCHANDISE AUTHORIZATION (RMA) NUMBER.

Appendix C - Electrical Interface
Sealevel Systems SeaLINK+485I Page 13
Appendix C - Electrical Interface
RS-422
The RS-422 specification defines the electrical characteristics of balanced
voltage digital interface circuits. RS-422 is a differential interface that defines
voltage levels and driver/receiver electrical specifications. On a differential
interface, logic levels are defined by the difference in voltage between a pair of
outputs or inputs. In contrast, a single ended interface, for example RS-232,
defines the logic levels as the difference in voltage between a single signal and a
common ground connection. Differential interfaces are typically more immune
to noise or voltage spikes that may occur on the communication lines.
Differential interfaces also have greater drive capabilities that allow for longer
cable lengths. RS-422 is rated up to 10 Megabits per second and can have
cabling 4000 feet long. RS-422 also defines driver and receiver electrical
characteristics that will allow 1 driver and up to 32 receivers on the line at once.
RS-422 signal levels range from 0 to +5 volts. RS-422 does not define a
physical connector.
RS-485
RS-485 is backwardly compatible with RS-422; however, it is optimized for
partyline or multi-drop applications. The output of the RS-422/485 driver is
capable of being Active (enabled) or Tri-State (disabled). This capability
allows multiple ports to be connected in a multi-drop bus and selectively polled.
RS-485 allows cable lengths up to 4000 feet and data rates up to 10 Megabits
per second. The signal levels for RS-485 are the same as those defined by
RS-422. RS-485 has electrical characteristics that allow for 32 drivers and 32
receivers to be connected to one line. This interface is ideal for multi-drop or
network environments. RS-485 tri-state driver (not dual-state) will allow the
electrical presence of the driver to be removed from the line. Only one driver
may be active at a time and the other driver(s) must be tri-stated. RS-485 can be
cabled in two ways, two wire and four wire mode. Two wire mode does not
allow for full duplex communication and requires that data be transferred in
only one direction at a time. For half-duplex operation, the two transmit pins
should be connected to the two receive pins (Tx+ to Rx+ and Tx- to Rx-). Four
wire mode allows full duplex data transfers. RS-485 does not define a connector
pin-out or a set of modem control signals. RS-485 does not define a physical
connector.

Appendix C - Electrical InterfaceGround Loop Phenomenon
Appendix D - Ground Loop Phenomenon
What is Ground Loop?
Ground loop Phenomenon occurs when two (or more) pieces of equipment are
connected together with a common ground and a different ground potential
exists at each location. This current can cause the connected equipment to
experience noise that in turn causes data transmission errors. In extreme cases
ground current can cause equipment malfunction or even destruction.
Cabling Recommendations
When connecting the SeaLINK+485I in an RS-485 network, care should be
taken that both ends of the network are not isolated from ground (see Figure 4).
This “floating” ground condition could cause capacitive or inductive coupling of
voltages that will cause a break down in the DC to DC converter circuit or in the
opto-isolator circuit. This condition will cause data errors and possibly
destruction of the receiver circuit.
AB
Isolation
Barrier
DATA+
DATA-
Ground
Isolated
Adapter
Non
Isolated
Adapter
Figure 4 – SeaLINK+485I cabling example
Sealevel Systems SeaLINK+485I Page 14

Appendix E - Asynchronous Communications
Appendix E - Asynchronous Communications
Serial data communications implies that individual bits of a character are
transmitted consecutively to a receiver that assembles the bits back into a
character. Data rate, error checking, handshaking, and character framing
(start/stop bits) are pre-defined and must correspond at both the transmitting and
receiving ends.
Asynchronous communications is the standard means of serial data
communication for PC compatibles and PS/2 computers. The original PC was
equipped with a communication or COM: port that was designed around an
8250 Universal Asynchronous Receiver Transmitter (UART). This device
allows asynchronous serial data to be transferred through a simple and
straightforward programming interface. Character boundaries for asynchronous
communications are defined by a starting bit followed by a pre-defined number
of data bits (5, 6, 7, or 8). The end of the character is defined by the
transmission of a pre-defined number of stop bits (usually 1, 1.5 or 2). An extra
bit used for error detection is often appended before the stop bits.
Remain Idle o
r
next start bit
Odd, Even
or
Unused
STOP
P
BIT
5 to 8 Data Bits
Idle state of
line
1
0
1
1.5
2
Figure 5 - Asynchronous Communications Bit Diagram
This special bit is called the parity bit. Parity is a simple method of determining
if a data bit has been lost or corrupted during transmission. There are several
methods for implementing a parity check to guard against data corruption.
Common methods are called (E)ven Parity or (O)dd Parity. Sometimes parity is
not used to detect errors on the data stream. This is refereed to as (N)o parity.
Because each bit in asynchronous communications is sent consecutively, it is
easy to generalize asynchronous communications by stating that each character
is wrapped (framed) by pre-defined bits to mark the beginning and end of the
serial transmission of the character. The data rate and communication
parameters for asynchronous communications have to be the same at both the
transmitting and receiving ends. The communication parameters are baud rate,
parity, number of data bits per character, and stop bits (i.e. 9600,N,8,1).
Sealevel Systems SeaLINK+485I Page 15

Appendix F – Silk Screen
Appendix F - Silk-Screen
3.28 in
2.09 in
1.39 in
Sealevel Systems SeaLINK+485I Page 16

Appendix G - Compliance Notices
Appendix G - Compliance Notices
Federal Communications Commission Statement
FCC - This equipment has been tested and found to comply with the limits for
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 such case the user will be required to correct the
interference at his own expense.
EMC Directive Statement
Products bearing the CE Label fulfill the requirements of
the EMC directive (89/336/EEC) and of the low-voltage
directive (73/23/EEC) issued by the European
Commission.
To obey these directives, the following European standards must be met:
EN55022 Class B - ‘Limits and methods of measurement of radio
interference characteristics of information technology equipment’
EN55024-‘Information technology equipment Immunity
characteristics Limits and methods of measurement.
EN60950 (IEC950) - ‘Safety of information technology
equipment, including electrical business equipment’
Always use cabling provided with this product if possible. If no cable is
provided or if an alternate cable is required, use high quality shielded cabling to
maintain compliance with EMC directives.
Sealevel Systems SeaLINK+485I Page 17

Warranty
Warranty
Sealevel Systems, Inc. provides a lifetime warranty for
this product. Should this product fail to be in good
working order at any time during this period, Sealevel
Systems will, at it's option, replace or repair it at no
additional charge except as set forth in the following terms. This warranty does
not apply to products damaged by misuse, modifications, accident or disaster.
Sealevel Systems assumes no liability for any damages, lost profits, lost savings
or any other incidental or consequential damage resulting from the use, misuse
of, or inability to use this product. Sealevel Systems will not be liable for any
claim made by any other related party.
RETURN AUTHORIZATION MUST BE OBTAINED FROM
SEALEVEL SYSTEMS BEFORE RETURNED MERCHANDISE WILL
BE ACCEPTED. AUTHORIZATION CAN BE OBTAINED BY
CALLING SEALEVEL SYSTEMS AND REQUESTING A RETURN
MERCHANDISE AUTHORIZATION (RMA) NUMBER.
Sealevel Systems, Incorporated
2779 Greenville Highway
P.O. Box 830
Liberty, SC 29657 USA
[phone] FAX: [phone]
www.sealevel.com
email: [email protected]
Technical Support is available from 8 a.m. to 5 p.m. Eastern time.
Monday - Friday
Trademarks
Sealevel Systems, Incorporated acknowledges that all trademarks referenced in
this manual are the service mark, trademark, or registered trademark of the
respective company.
SeaLINK+485I is a trademark of Sealevel Systems, Incorporated.
Sealevel Systems SeaLINK+485I Page 18