SeaLevel COMM+4/422.PCIe User manual

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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
COMM+4/422.PCIe
User Manual | 7402e and 7402eS

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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
Contents
CONTENTS...........................................................................................................................................................2
INTRODUCTION ................................................................................................................................................... 3
BEFORE YOU GET STARTED ...............................................................................................................................5
HARDWARE DESCRIPTION ................................................................................................................................. 7
HARDWARE CONFIGURATION............................................................................................................................8
SOFTWARE INSTALLATION..............................................................................................................................11
TECHNICAL DESCRIPTION ...............................................................................................................................13
SPECIFICATIONS ...............................................................................................................................................15
APPENDIX A – TROUBLESHOOTING................................................................................................................16
APPENDIX B – HANDLING INSTRUCTIONS.....................................................................................................17
APPENDIX C – ELECTRICAL INTERFACE ........................................................................................................18
APPENDIX D – ASYNCHRONOUS COMMUNICATIONS ..................................................................................19
APPENDIX E – MECHANICAL DRAWING .........................................................................................................20
WARRANTY ........................................................................................................................................................21
................................................................................................................................................................................

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Introduction
The Sealevel COMM+2.422.PCIe (Item# 7402e) provides a PCI Express 1.0a compliant interface adapter
with four asynchronous serial ports for industrial automation and control applications. The serial ports are
field selectable for RS-422 or RS-485 and support data rates to 921.6 Kbps.
RS-422 mode for is designed for long distance device connections up to 4000ft. where noise immunity and
high data integrity are essential. RS-485 mode can capture data from multiple peripherals in an RS485
multi-drop network. Up to 31 unit load RS-485 devices can be connected to each port to automate your data
collection. You can even mix the ports in any of the interface combinations to provide maximum flexibility
to your application.
In RS-485 mode, the transmitter is automatically enabled in hardware, eliminating the need for application
software control. This allows the 7402e to be used with standard serial communications applications and
removes the risk of bus contention and data corruption.
The 7402e ships with a low profile PC bracket for use in systems with a low profile PCI Express slot. If you
need a standard size PC bracket, order the 7402eS.
Features
•PCI Express four-port serial interface adapter
•Each port individually configurable for RS-422 or RS-485
•High performance OXPCIe954 UART with 128-byte FIFOs
•Each port supports data rates to 921.6K bps
•Oscillator and clock prescaler support wide range of baud rates
•Supports 9-bit protocol framing
•PCI Express 1.0a compliant via x1 connector
•Compatible with all low profile and standard size PCI Express slots
•Includes 36” cable that terminates to four DB9M connectors (Item# CA200)
•Automatic RS-485 enable/disable

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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
Before You Get Started
What’s Included
The COMM+4.422.PCIe is shipped with the following items. If any of these items are missing or damaged,
please contact Sealevel for replacement.
•COMM+422.PCIe Serial I/O Adapter – Four-Port 422/485 Serial Interface
•7402e – PCI Express Board with Low Profile PC Bracket
•7402eS – PCI Express Board with Standard Height PC Bracket
•CA200 - DB44 Male to (4) DB9 Male Cable
Advisory Conventions
Warning
The highest level of importance used to stress a condition where damage could result to the
product, or the user could suffer serious injury.
Important
The middle level of importance used to highlight information that might not seem obvious or a
situation that could cause the product to fail.
Note
The lowest level of importance used to provide background information, additional tips, or other
non-critical facts that will not affect the use of the product.

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Optional Items
Depending upon your application, you are likely to find one or more of the following items useful with the
COMM+4.422.PCIe. All items can be purchased from our website (www.sealevel.com) by calling our Sales
team at [phone].
DB9 to DB25 Serial Cable (Item# CA176)
DB9 Female (RS-422) to DB25 Male (RS-530) Cable, 10
in Length
DB9 to DB25 Serial Cable (Item# CA177)
DB9 Female to DB25 Male Standard RS-232 Modem
Cable, 72 inch Length
DB9 Serial Extension Cable (Item# CA127)
DB9 Female to DB9 Male Extension Cable, 72 inch
Length
Terminal Block Kit (Item# KT106)
Terminal Block Kit - TB06 + (2) CA127 Cables
Terminal Block Kit (Item# KT105)
Terminal Block Kit - TB05 + CA127 Cable
Terminal Block Kit (Item# TB34-4)
Terminal Block Kit (4 Pack) - DB9 Female to 5 Screw
Terminals (RS-422/485)

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Hardware Description
PCI Express Board
The 7402e is a low profile PCI Express 1.0a compliant board via single lane x1 slot. It can be used in any
single- or multi-lane PCI Express slot. It is available in standard height PCI Express as item# 7402eS.
DB44F Board Connector
The board integrates a DB44 female connector for interfacing the four serial ports via the included cable.
DB25M Serial Connectors
The 7402e ships with a four-port cable (Item# CA200) that includes four DB9 male serial connectors. The
pin out for these connectors is detailed in the following Technical Description section.

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Hardware Configuration
Address and IRQ selection
The COMM+4.422.PCIe is automatically assigned I/O addresses and IRQs by your motherboard BIOS or by
a ‘Plug-n-Play’ Operating System. Adding or removing other hardware or moving the adapter to another slot
may change the assignment of I/O addresses and IRQs.
Clock Modes
The COMM+4.422.PCIe derives a 62.5MHz clock from the PCI express link which is divided by a 8 bit clock
prescaler and a 16 bit clock divisor to provide a wide range of possible baud rates. Note that there are
many combinations that can give the same result (e.g. Prescaler=1 and Divisor = 8, Prescaler =2 and Divisor
= 4, or Prescaler=8 and Divisor = 1). As long as the calculated data rate is within +/- 2% you should
communicate fine.
Baud Rates
The following table shows some common data rates and the rates you should choose to achieve them
when using the COMM+4.422.PCIe.
For This Data Rate Clock Prescaler Choose This Divisor DLM:DLL
1200 bps 1 3255
2400 bps 3.625 449
4800 bps 1.875 434
9600 bps 1.875 217
19.2K bps 1.375 148
38.4K bps 1.375 74
57.6K bps 22.625 3
115.2K bps 1 34
230.4K bps 1 17
460.8K bps 2.125 4
921.6K bps 2.125 2

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Electrical Interface Selection
Each of the four ports on the COMM+4.422.PCIe can be individually configured as an, RS-422, or RS-485
interface. This is selectable via the port DIP-switch; each is labeled with its port number.
Switch 1 (Silk M1) Switch 2 (Silk M0) Mode Select
OFF OFF RESERVED
OFF ON 422
ON OFF 485 With Echo
ON ON 485 No Echo
Line Termination
Typically, each end of the RS-485 bus must have line-terminating resistors (RS-422 terminates at the receive
end only). A 120-ohm resistor is across each RS-422/485 input in addition to a 1K-ohm pull-up/pull-down
combination that biases the receiver inputs. Each switch allows customization of this interface to specific
requirements. Each switch position corresponds to a specific portion of the interface. If multiple
COMM+4.422.PCIe adapters are configured in an RS-485 network, only the boards on each end should have
switches T, P & P ON. Refer to the following table for each position’s operation:
Switch Name Function
3 T Adds or removes the 120 ohm termination.
4 PU Adds or removes the 1K ohm pull-up resistor in the RS-422/RS-485 receiver circuit
5 PD Adds or removes the 1K ohm pull-down resistor in the RS-422/RS-485 receiver circuit
6 L Connects the TX- to RX- for RS-485 two-wire operation.
7 L Connects the TX+ to RX+ for RS-485 two-wire operation.
RS-485 ‘Echo’
In ‘RS-485 With Echo’ mode both the receiver and the transmitter are enabled simultaneously. Every time a
character is transmitted, it is also received. This can be beneficial if the software can handle echoing (i.e.
using received characters to throttle the transmitter) or it can confuse the system if the software does not.
An RS-485 ‘No Echo’ option is selected by placing both Mode switches (M0, M1) in the ‘On’ position.

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Figure 1 - RS-422 Mode
Figure 2 - RS-485 two-wire with 'Echo'
Figure 3 - RS-485 two-wire No 'Echo'
1234567
ON
123 4 5 6 7
ON
1234567
ON

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Software Installation
Windows Installation
Do not connect the hardware until the software has been fully installed.
Only users running Windows 7 or newer should utilize these instructions for accessing and
installing the appropriate driver via Sealevel’s website. If you are utilizing an operating system
prior to Windows 7, please contact Sealevel by calling 864.843.4343 or emailing
[email protected] to receive access to the proper driver download and installation
instructions.
1. Begin by locating, selecting, and installing the correct software from the Sealevel software
driver database.
2. Type in or select the part number (#7402e) for the adapter from the listing.
3. Select “Download Now” for SeaCOM for Windows.
4. The setup files will automatically detect the operating environment and install the proper
components. Follow the information presented on the screens that follow.
5. A screen may appear with text similar to: “The publisher cannot be determined due to the
problems below: Authenticode signature not found.” Please click 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.
6. During setup, the user 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 also included
to remove all registry/INI file entries from the system.
7. The software is now installed, and you can proceed with the hardware installation.
To install Sealevel software, you must log in as an administrator or have administrator privileges in
Windows. All Sealevel Systems software drivers have been fully tested by Sealevel. Clicking “OK”
button to continue.
This is a notification that if you are upgrading from a previous driver version, you should remove
the associated Device Manager hardware entries and reinstall the adapter after the installing the
SeaCOM software.

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Upgrading to the Current SeaCOM Driver
1. Download the current driver using the Instructions from the Where to Get Software section
above. Please take note of the destination directory it will save to.
2. Uninstall the currently loaded driver SeaCOM driver found in the Control Panel. Prior to
Windows Vista SeaCOM will be populated in ‘Add/Remove Programs’ list. In Vista and newer
OSs it will be found in the ‘Programs and Features’ list.
3. Navigate to the Device Manager and remove the Sealevel adapter by right clicking on the line
item choosing ‘Uninstall’. Depending on your product, it can be found under either ‘Multiport
Serial adapters’ or ‘Universal Serial Bus controllers’.
4. In the Device Manager under ‘Action’, choose ‘Scan for Hardware changes’. This will prompt
the installation of the adapter and associate it with the newly installed SeaCOM driver.
Linux Installation
You MUST have “root” privileges to install the software and drivers.
The syntax is case sensitive.
SeaCOM for Linux can be downloaded here: https://www.sealevel.com/support/software-seacom-linux/.
It includes the README and the Serial-HOWTO help files (located at seacom/dox/howto). This series of
files both explains typical Linux serial implementations and informs the user about Linux syntax and
preferred practices.
User can use a program such as 7-Zip to extract the tar.gz file.
In addition, the software selectable interface settings can be accessed by referencing
seacom/utilities/7402emode.
Linux Support
The 7402e is supported natively in Linux kernels 2.6.28 and later.
For additional software support, please call Sealevel Systems’ Technical Support, [phone]. Our
technical support is free and available from 8:00 AM - 5:00 PM Eastern Time, Monday through Friday. For
email support contact: [e-mail].

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Technical Description
The COMM+4.422.PCIe provides four RS-422/485 ports from a single PCIe slot.
The COMM+4.422.PCIe utilizes the OXPCIe954 type UART. This chip features programmable baud rates,
data format, interrupt control and industry leading 128-byte transmit and receive FIFOs.
The UARTs are register compatible with 16C450, 16C550, 16C654 and 16C750 UARTs. The FIFO depth
can be changed to match the depth of these UARTs.
RS-422/485 (CA-200 DB-9) Connector Pin Assignments
Signal Name Pin # Mode
GND Ground 5
TX + Transmit Data Positive 4 Output
TX- Transmit Data Negative 3 Output
RTS+ Request To Send
Positive
6 Output
RTS- Request To Send
Negative
7 Output
RX+ Receive Data Positive 1 Input
RX- Receive Data Negative 2 Input
CTS+ Clear To Send Positive 9 Input
CTS- Clear To Send Negative 8 Input

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RS-422/485 (DB-44)
Port # 1 2 3 4
RS-
422/485
TX- 1 5 9 13
RX- 4 8 12 30
RTS- 2 6 10 14
CTS- 16 20 23 27
TX+ 32 36 40 43
RTS+ 31 35 39 42
RX+ 3 7 11 15
CTS+ 33 37 41 44
GND 17 21 24 28
The RTS output is only available in RS-422 mode. The RTS output is tri-stated in RS-485 mode
and therefore unusable. The CTS input is available in all modes. Terminating these pins, if not
used, will help ensure you get the best performance from your adapter.

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Specifications
Environmental Specifications
Specification Operating Storage
Temperature Range 0º to 70º C (32º to 158º F) -50º to 105º C (-58º to 221º 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 +3.3 VDC +12VDC
Rating 100 mA 25 mA

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Appendix A – Troubleshooting
The adapter should provide years of trouble-free service. However, in the event that device appears to not
be functioning incorrectly, the following tips can eliminate most common problems without the need to call
Technical Support.
1. Identify all I/O adapters currently installed in your system. This includes your on-board serial ports,
controller cards, sound cards etc. The I/O addresses used by these adapters, as well as the IRQ (if
any) should be identified.
2. Configure your Sealevel Systems adapter so that there is no conflict with currently installed
adapters. No two adapters can occupy the same I/O address.
3. Make sure the Sealevel Systems adapter is using a unique IRQ The IRQ is typically selected via an
on-board header block. Refer to the section on Card Setup for help in choosing an I/O address and
IRQ.
4. Make sure the Sealevel Systems adapter is securely installed in a motherboard slot.
5. If you are utilizing an operating system prior to Windows 7, please contact Sealevel‘s Technical
support as directed below to receive more information regarding the utility software which will
determine if your product is functioning properly.
6. Only users running Windows 7 or newer should utilize the diagnostic tool ‘WinSSD’ installed in the
SeaCOM folder on the Start Menu during the setup process. First find the ports using the Device
Manager, then use ‘WinSSD’ to verify that the ports are functional.
7. Always use the Sealevel Systems diagnostic software when troubleshooting a problem. This will
help eliminate any software issues and identify any hardware conflicts.
If these steps do not solve your problem, please call Sealevel Systems’ Technical Support, [phone].
Our technical support is free and available from 8:00 A.M.- 5:00 P.M. Eastern Time Monday through Friday.
For email support contact [e-mail].

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Appendix B – Handling Instructions
ESD Warnings
Electrostatic Discharges (ESD)
•A sudden electrostatic discharge can destroy sensitive components. Proper packaging and
grounding rules must therefore be observed. Always take the following precautions:
Transport boards and cards in electrostatically secure containers or bags.
•Keep electrostatically sensitive components in their containers, until they arrive at an
electrostatically protected workplace.
•Only touch electrostatically sensitive components when you are properly grounded.
•Store electrostatically sensitive components in protective packaging or on anti-static mats.
Grounding Methods
The following measures help to avoid electrostatic damages to the device:
•Cover workstations with approved antistatic material. Always wear a wrist strap connected to a
properly grounded workplace.
•Use antistatic mats, heel straps, and/or air ionizers for more protection.
•Always handle electrostatically sensitive components by their edge or by their casing.
•Avoid contact with pins, leads, or circuitry.
•Turn off power and input signals before inserting and removing connectors or connecting test
equipment.
•Keep work area free of non-conductive materials such as ordinary plastic assembly aids and
Styrofoam.
•Use field service tools such as cutters, screwdrivers, and vacuum cleaners that are conductive.

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Appendix C – Electrical Interface
RS-232
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 party line 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.

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Appendix D – 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 Unil Asynchronous Receiver Transmitter (UART). This device allows asynchronous serial
data to be transferred through a simple and straightforward programming interface. A starting bit followed
by a pre-defined number of data bits (5, 6, 7, or 8) defines character boundaries for asynchronous
communications. 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.
Figure 4 - 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 referred 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).
Remain Idle or
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

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Appendix E – Mechanical Drawing