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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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
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

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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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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
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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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
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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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
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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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
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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© Sealevel Systems, Inc. 7402e Manual | SL925111/2022
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