Impulse 7203 User Manual

SO COMM2.PCI

USER MANUAL

Sealevel Systems, Inc

P.O. Box 830 Liberty, SC 29657 USA

Part # 7203

Phone: (864) 843-4343 FAX: (864) 843-3067 www.sealevel.com

INTRODUCTION ........................................................................ 1

OVERVIEW......................................................................................1

WHAT’S INCLUDED.........................................................................1

FACTORY DEFAULT SETTINGS ........................................................1

CARD SETUP ............................................................................ 2

ELECTRICAL INTERFACE SELECTION...............................................2

LINE TERMINATION ........................................................................3

RS-485 ENABLE MODES ................................................................4

CLOCK MODES ...............................................................................5

BAUD RATES AND DIVISORS FOR THE ‘DIV1’ MODE .......................6

INSTALLATION ......................................................................... 7

OPERATING SYSTEM INSTALLATION ...............................................7

For Windows Users.....................................................................7

Other Operating Systems ............................................................7

SYSTEM INSTALLATION ..................................................................7

TECHNICAL DESCRIPTION ...................................................... 8

CONNECTOR PIN ASSIGNMENTS......................................................8

RS-232 ........................................................................................8

RS-422/485.................................................................................8

SPECIFICATIONS ...................................................................... 9

ENVIRONMENTAL SPECIFICATIONS .................................................9

MANUFACTURING...........................................................................9

POWER CONSUMPTION ...................................................................9

MEAN TIME BETWEEN FAILURES (MTBF) .....................................9

PHYSICAL DIMENSIONS...................................................................9

PPENDIX A - TROUBLESHOOTING ...................................... 10

APPENDIX B - HOW TO GET ASSISTANCE............................ 11

APPENDIX C - ELECTRICAL INTERFACE .............................. 12

RS-232.........................................................................................12

RS-422.........................................................................................12

RS-485.........................................................................................13

APPENDIX D - GROUND LOOP PHENOMENON ...................... 14

WHAT IS GROUND LOOP? .............................................................14

CABLING RECOMMENDATIONS .....................................................14

APPENDIX E - ASYNCHRONOUS COMMUNICATIONS ............ 15

APPENDIX F - SILK-SCREEN ................................................. 16

APPENDIX G - COMPLIANCE NOTICES ................................. 17

FEDERAL COMMUNICATIONS COMMISSION STATEMENT...............17

EMC DIRECTIVE STATEMENT ......................................................17

WARRANTY............................................................................ 18

Figures

Figure 1- RS-232 ........................................................................................2

Figure 2 - RS-422 .......................................................................................2

Figure 3 - RS-485, 4-Wire with Echo ......................................................2

Figure 4 - RS-485 2-Wire with Echo ........................................................2

Figure 5 - RS-485, 2-wire without Echo...................................................3

Figure 6 - RS-485 Enable modes...............................................................4

Figure 7 - Clocking Modes ........................................................................5

Figure 8 – ISO COMM +2 cabling example ..........................................14

Figure 9 - Asynchronous Communications Bit Diagram......................15

Introduction

Overview

The Sealevel Systems ULTRA COMM+2I.PCI is a two channel isolated PCI Bus serial I/O adapter for the PC and compatibles. Utilizing the Exar 16C850 UART with its industry leading 128 byte FIFOs, it provides two field selectable RS-232/422/485 serial ports supporting data rates up to 460.8K bps (RS-422/485).

Configure both ports as RS-232 for standard serial COM: port requirements. Choose the RS-422 mode for long distance device connections up to 5000ft. where noise immunity and high data integrity are essential. Select RS-485 and capture data from multiple peripherals in a RS-485 multidrop network. Up to 31 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. Optional Terminal Block adapters are available to simplify field-wiring connections.

In both RS-232 and RS-422 modes, the card works seamlessly with the standard operating system serial driver. In RS-485 mode, our special auto-enable feature allows the RS-485 ports to be viewed by the operating system as a COM: port. This allows the standard COM: driver to be utilized for RS-485 communications. Our on-board hardware automatically handles the RS-485 driver enable.

What’s Included

The ULTRA COMM+2I.PCI is shipped with the following items. If any of these items is missing or damaged, contact the supplier.

• ULTRA COMM+2I.PCI Serial I/O Adapter

• Sealevel Software

Factory Default Settings

The ULTRA COMM+2I.PCI factory default settings are as follows:

Port # Electrical Specification

Port 1 RS-422 Port 2 RS-422

To install the ULTRA COMM+2I.PCI using factory default settings, refer to Installation on page 7.

Sealevel Systems ULTRA COMM+2I.PCI Page 1

Card Setup

Electrical Interface Selection

Each port on the ULTRA COMM+2I.PCI has the ability to be used as RS-232, RS-422 or RS-485. This is selectable via two DIP-switches, SW1 & SW2. Please use the following examples to configure your adapter.

RS-232

RS-422

OFF

1 2 3 4 5 6 7

123TPPLLE

Figure 1- RS-232

OFF

1 2 3 4 5 6 7

123TPPLLE

Figure 2 - RS-422

8 9 10

4-Wire

RS-485

W/Echo

OFF

1 2 3 4 5 6 7

8 9 10

123TPPLLE

Figure 3 - RS-485, 4-Wire with Echo

2-Wire

RS-485

W/Echo

OFF

1 2 3 4 5 6 7

8 9 10

123TPPLLE

Figure 4 - RS-485 2-Wire with Echo

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Card Setup

2-Wire

RS-485

NO Echo

OFF

1 2 3 4 5 6 7

8 9 10

123TPPLLE

Figure 5 - RS-485, 2-wire without 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. Switches SW1 and SW2 allow the user to customize this interface to their specific requirements. Each switch position corresponds to a specific portion of the interface. If multiple ULTRA COMM+2I.PCI adapters are configured in a RS-485 network, only the boards on each end should have jumpers T, P & P ON. Refer to the following table for each position’s operation:

Name Function

T Adds or removes the 120 ohm termination. P Adds or removes the 1K ohm pull-down resistor in the

RS-422/RS-485 receiver circuit (Receive data only).

P Adds or removes the 1K ohm pull-up resistor in the RS-422/RS-

485 receiver circuit (Receive data only). L Connects the TX+ to RX+ for RS-485 two wire operation. L Connects the TX- to RX- for RS-485 two wire operation.

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Card Setup

RS-485 Enable Modes

RS-485 is ideal for multi-drop or network environments. RS-485 requires a tri-state driver that will allow the electrical presence of the driver to be removed from the line. The driver is in a tri-state or high impedance condition when this occurs. Only one driver may be active at a time and the other driver(s) must be tri-stated. The output modem control signal Request To Send (RTS) is typically used to control the state of the driver. Some communication software packages refer to RS-485 as RTS enable or RTS block mode transfer.

One of the unique features of the ULTRA COMM+2I.PCI is the ability to be RS-485 compatible without the need for special software or drivers. This ability is especially useful in Operating Systems where the lower level I/O control is abstracted from the application program. This ability means that the user can effectively use the ULTRA COMM+2I.PCI in an RS-485 application with existing (i.e. standard RS-232) software drivers.

Switches SW3 and SW4 are used to control the RS-485 mode functions for the driver circuit. The selections are ‘RTS’ enable (silk-screen ‘RT’ switch position

4) or ‘Auto’ enable (silk-screen ‘AT’ switch position 3). The ‘Auto’ enable feature automatically enables/disables the RS-485 interface. The ‘RTS’ mode uses the ‘RTS’ modem control signal to enable the RS-485 interface and provides backward compatibility with existing software products.

The RS-485 ‘Echo’ is the result of connecting the receiver inputs to the transmitter outputs. 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. Position 9 of SW1 and SW2 is used to control the RS-485 enable/disable functions for the receiver circuit. To select the ‘No Echo’ mode place switch position 9 to the ‘On’ position (see Figure 5).

SW3

RS-232/422

Default

SW4

OFF

1 2 3 4

D1D4ATR

OFF

1 2 3 4

SW3

RS-485

Auto

Enabled

SW4

OFF

1 2 3 4

D1D4ATR

OFF

1 2 3 4

Figure 6 - RS-485 Enable modes

Sealevel Systems ULTRA COMM+2I.PCI Page 4

+ 14 hidden pages

Impulse 7203 User Manual

Contents

Introduction

Card Setup