SEALEVEL COMM+8.422.PCIe Isolated Serial Interface User Manual

June 12, 2024
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SEALEVEL COMM+8.422.PCIe Isolated Serial Interface

SEALEVEL-COMM-8-422-PCIeIsolated-Serial-Interface-
product

Product Information

The COMM+8.422.PCIe is a PCI Express board designed for serial communication. It is compliant with the PCI Express 1.0a standard and can be used in any single- or multi-lane PCI Express slot. The board features a low profile design and is available in standard height PCI Express as item# 7802eS.

The board integrates a 68-pin female connector for interfacing with the serial ports. It comes with an eight-port cable (Item# CA231) that includes eight DB9 male serial connectors. The pinout for these connectors is detailed in the user manual. Each of the eight ports on the COMM+8.422.PCIe can be individually configured as an RS-422 or RS-485 interface. The interface selection is done using the port DIP switch, with each switch labeled with its corresponding port number.

Product Usage Instructions

  1. Before getting started, ensure that all the items are included in the package. If any item is missing or damaged, contact Sealevel for replacement.
  2. Optional items for interfacing the COMM+8.422.PCIe to real-world signals can be purchased from the Sealevel website or by calling 864-843-4343.
  3. To configure the hardware, follow these steps:
    • Address and IRQ Selection: The COMM+8.422.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+8.422.PCIe derives a 62.5MHz clock from the PCI Express link. The clock is divided by an 8-bit clock prescaler and a 16-bit clock divisor to provide a wide range of possible baud rates. Choose the appropriate combination of prescaler and divisor to achieve the desired data rate. As long as the calculated data rate is within +/- 2%, communication should work fine.
    • Baud Rates: Refer to the provided table in the user manual to choose the correct clock prescaler and divisor for common data rates.
    • Electrical Interface Selection: Each port on the COMM+8.422.PCIe can be configured as an RS-422 or RS-485 interface. Use the port DIP switches labeled with their respective port numbers to select the desired interface.

Introduction

The Sealevel COMM+8.422.PCIe (Item# 7802e) provides a PCI Express 1.0a compliant interface adapter with eight 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 RS485 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 7802e to be used with standard serial communications applications and removes the risk of bus contention and data corruption. The Sealevel SeaCOM software driver and utilities make installation and operation easy XP, Vista, Windows 7, and Windows 8 operating systems. The 7802e 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 7802eS.

Features

  • PCI Express eight-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 eight DB9M connectors
  • Automatic RS-485 enable/disable

Before You Get Started

What’s Included

The COMM+8.422.PCIe is shipped with the following items. If any of these items are missing or damaged, please contact Sealevel for replacement.

  • COMM+8.422.PCIe Serial I/O Adapter – Four-Port 422/485 Serial Interface
  • 7802e – PCI Express Board with Low Profile PC Bracket
  • 7802eS – PCI Express Board with Standard Height PC Bracket
  • CA231 – 68 pin Male to (8) 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.

Optional Items

  • Depending upon your application, you are likely to find one or more of the following items useful for interfacing the COMM+8.422.PCIe to real-world signals. All items can be purchased from our website (www.sealevel.com) or by calling 864-843-4343.

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# TB34-8)
Terminal Block Kit (8 Pack) – DB9 Female to 5 Screw Terminals (RS-422/485)|

Hardware Description

SEALEVEL-COMM-8-422-PCIeIsolated-Serial-Interface-
fig-4

PCI Express Board

  • The 7802e 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# 7802eS.

68Pin Board Connector

  • The board integrates a 68 pin female connector for interfacing the serial ports via the included cable.

DB9M Serial Connectors

  • The 7802e ships with an eight-port cable (Item# CA231) that includes eight DB9 male serial connectors. The pin out for these connectors is detailed in the following Technical Description section.

Hardware Configuration

Address and IRQ selection

The COMM+8.422.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+8.422.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+8.422.PCIe.

For This Data Rate| Clock Prescaler| Choose This Divisor DLM:DLL
---|---|---
1200 bps| 3.625| 898
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

Electrical Interface Selection

  • Each of the eight ports on the COMM+8.422.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+8.422.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’

SEALEVEL-COMM-8-422-PCIeIsolated-Serial-Interface-
fig-5

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.

Installation & Configuration

Windows Installation

Warning: 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 (#7802e) 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.

Note: Do not connect the hardware until the software has been successfully installed. To install Sealevel software, you must log in as an administrator or have administrator privileges in Windows.

Warning: To install Sealevel software, you must log in as an administrator or have administrator privileges in Windows.

Upgrading to the Current SeaCOM Driver

  1. Download the current driver using the Instructions from the Windows Installation section on Page 10. 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

_ Note: _You MUST have “root” privileges to install the software and drivers.

Warning: 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.

Note: 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/7802emode.

Linux Support

  • The 7802e is supported natively in Linux kernels 2.6.28 and later.
  • For additional software support, please call Sealevel Systems’ Technical Support, 864-843-4343. Our technical support is free and available from 8:00 AM – 5:00 PM Eastern Time, Monday through Friday. For email support contact: [email protected].

Technical Description

  • The COMM+8.422.PCIe provides eight RS-422/485 ports from a single PCIe slot.
  • The COMM+8.422.PCIe utilizes the OXPCIe954 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-231 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

RS-422/485 (68 Pin)

Port # 1 2 3 4 5 6 7 8
TX- 1 9 19 27 35 43 53 61
RX- 7 15 25 33 41 49 59 67
RTS- 5 13 23 31 39 47 57 65
CTS- 8 16 26 34 42 50 60 68
TX+ 4 12 22 30 38 46 56 64
RTS+ 6 14 24 32 40 48 58 66
RX+ 3 11 21 29 37 45 55 63
CTS+ 2 10 20 28 36 44 54 62
GND 17 17 18 18 51 51 52 52

Note

  • Please terminate any control signals that are not going to be used. The most common way to do this is connect RTS to CTS and RI. Also, connect DCD to DTR and DSR. Terminating these pins, if not used, will help ensure you get the best performance from your adapter.
  • 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.

Specifications

Environmental Specifications

Specification Operating Storage
Temperature Range 0° to 70°C (32° to 158°F) -50° to 105°C (-58° to

221°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.

Power Requirements

Supply line +3.3 VDC +12 VDC
Rating 100 mA 25 mA

Appendix A – Troubleshooting

Following these simple steps can eliminate most common problems.

  1. Read this manual thoroughly before attempting to install the adapter in your system.
  2. Install software first. This places the required installation files in the correct locations. After installing the software, proceed to the physical installation section of this manual.
  3. 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.
  4. 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.
  5. Make sure the Sealevel Systems adapter is securely installed.
  6. For Windows 2000/XP/Vista, and Windows 7, the diagnostic tool ‘WinSSD’ is installed the SeaMAC 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. The Loopback tab is primarily designed for asynchronous cards and should not be used in synchronous modes – use the BERT tab instead.
  7. Always use Sealevel Systems diagnostic software when troubleshooting a problem. This will eliminate any software issues from the equation.

If these steps do not solve your problem, please call Sealevel Technical Support at +1864-843-4343. Our technical support is free and available Monday through Friday from 8:00 am – 5:00 pm EST. For email support, contact [email protected].

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 damage to the device:

  • Cover workstations with approved antistatic material. Always wear a wrist strap connected to the workstation as well as properly grounded tools and equipment.
  • Use antistatic mats, heel straps, 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.
  • 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, which are conductive.

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 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. RS-485 can be cabled in two ways, two wire and four wire modes. 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 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.

SEALEVEL-COMM-8-422-PCIeIsolated-Serial-Interface-
fig-6

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. 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.

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).

Appendix E – Mechanical Drawing

SEALEVEL-COMM-8-422-PCIeIsolated-Serial-Interface-
fig-7

Appendix F – How To Get Assistance

When calling for technical assistance, please have the device installed and ready to run diagnostics. If possible, have your user manual and current settings ready. The Sealevel website is an excellent resource located at www.sealevel.com. The most current software updates and user manuals are available via our homepage by clicking on the ‘Drivers’ or ‘Manuals’ links located under ‘Technical Support.’ Manuals and software can also be downloaded from the product page for your device. The FAQ section of our website answers many common questions. Refer to this helpful resource by visiting https://www.sealevel.com/support/category/faqs/.

Technical Support

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.

FCC STATEMENT

Federal Communications Commission (FCC) Statement

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 the user’s 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 A – “Limits and methods of measurement of radio interference characteristics of information technology equipment”
  • EN55024 – “Information technology equipment Immunity characteristics Limits and methods of measurement”.

Warning

  • This is a Class A Product. In a domestic environment, this product may cause radio interference in which case the user may be required to take adequate measures to prevent or correct the interference.
  • 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 FCC/EMC directives.

Warranty

Sealevel’s commitment to providing the best I/O solutions is reflected in the Lifetime Warranty that is standard on all Sealevel manufactured I/O products. We are able to offer this warranty due to our control of manufacturing quality and the historically high reliability of our products in the field. Sealevel products are designed and manufactured at its Liberty, South Carolina facility, allowing direct control over product development, production, burn- in and testing. Sealevel achieved ISO-9001:2015 certification in 2018.

Warranty Policy

Sealevel Systems, Inc. (hereafter “Sealevel”) warrants that the Product shall conform to and perform in accordance with published technical specifications and shall be free of defects in materials and workmanship for the warranty period. In the event of failure, Sealevel will repair or replace the product at Sealevel’s sole discretion. Failures resulting from misapplication or misuse of the Product, failure to adhere to any specifications or instructions, or failure resulting from neglect, abuse, accidents, or acts of nature are not covered under this warranty.

Warranty service may be obtained by delivering the Product to Sealevel and providing proof of purchase. Customer agrees to ensure the Product or assume the risk of loss or damage in transit, to prepay shipping charges to Sealevel, and to use the original shipping container or equivalent. Warranty is valid only for original purchaser and is not transferable. This warranty applies to Sealevel manufactured Product. Product purchased through Sealevel but manufactured by a third party will retain the original manufacturer’s warranty.

Non-Warranty Repair/Retest

Products returned due to damage or misuse and Products retested with no problem found are subject to repair/retest charges. A purchase order or credit card number and authorization must be provided in order to obtain an RMA (Return Merchandise Authorization) number prior to returning Product.

How to obtain an RMA (Return Merchandise Authorization)

If you need to return a product for warranty or non-warranty repair, you must first obtain an RMA number. Please contact Sealevel Systems, Inc. Technical Support for assistance:

Trademarks

Sealevel Systems, Incorporated acknowledges that all trademarks referenced in this manual are the service mark, trademark, or registered trademark of the respective company.

© Sealevel Systems, Inc.

References

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