Black Box LD485A-HS Manual
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Black Box LD485A-HS Manual

Black Box LD485A-HS Manual

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LD485A-HS Card
LD485A-HS Opto-Isolated
LD485A-HS Isolated Card
CUSTOMER
Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX
FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746
SUPPORT
Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
INFORMATION
Web site: www.blackbox.com • E-mail: info@blackbox.com
LD485A-HS
L D 4 8 5 A - H S
N O R M A L
D L B
L D 4 8 5 A - H S O
N O R M A L
D L B
ME837A-R2
ME837C-R2
ME838AE
BC00702
T S C D
R X T X R
D C E
P W R
D T E
R T S
C D
T X R X
E D
P T O - IS O L A T
R X T X R
D C E
D T E
T X R X
SEPTEMBER 1999
ME837AE
ME838A-R2
ME838C-R2
FA520A-R2
T S C D
P W R
R T S
C D

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  • Page 1 Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746 SUPPORT Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018 INFORMATION Web site: www.blackbox.com • E-mail: info@blackbox.com...
  • Page 2 FCC AND IC STATEMENTS FEDERAL COMMUNICATIONS COMMISSION INDUSTRY CANADA RADIO FREQUENCY INTERFERENCE STATEMENTS This equipment generates, uses, and can radiate radio frequency energy and if not installed and used properly, that is, in strict accordance with the manufacturer’s instructions, may cause interference to radio communication. It has been tested and found to comply with the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of FCC rules, which are designed to provide reasonable protection against...

  • Page 3: Table Of Contents

    LD485A-HS and LD485A-HS Opto-Isolated Contents Chapter Page 1. Specifications....................1 2. Introduction ....................3 3. Installation.......................4 3.1 Jumper and Switch Configuration............4 3.1.1 DTE/DCE Configuration............4 3.1.2 Frame Ground/Signal Ground ..........4 3.1.3 Half/Full-Duplex Operation.............5 3.1.4 CTS Delay...................7 3.1.5 RS-485 Driver Enable..............7 3.1.6 Half-Duplex Turnaround Delay ..........8 3.1.7 RS-485 Interface Terminated or Unterminated ......8...

  • Page 4: Specifications

    CHAPTER 1: Specifications 1. Specifications Optical Isolation: ME838A-R2, ME838AE, ME838C-R2 only Interface — (1) asynchronous RS-232 port (DTE/DCE selectable); (1) asynchronous RS-485 port with improved surge protection and switch-selectable line termination or line bias Connectors — (1) DB25, female—RS-232 port; (1) four-wire terminal block (TB1)—RS-485 port Pins Supported —...
  • Page 5 LD485A-HS and LD485A-HS Opto-Isolated Operation — Point to Point or Multipoint Half or Full Duplex Transparent to data Selectable RTS-to-CTS delay with option to inhibit CTS if CD is present (DCE) DTE or DCE configurable RS-232 port Normal or loopback operation Timeout Delay —...

  • Page 6: Introduction

    It allows an RS-232 device to transmit data over much longer distances than is normally possible (up to 4 miles—6.4 km—at 1200 bps). The advantage of the LD485A-HS over other line drivers and modems is that it can also operate in multipoint applications. Depending on the operating environment, as many as 64 devices can be linked together using twisted-pair cable.

  • Page 7: Installation

    A DIP shunt is used to select DTE or DCE configuration. For the LD485A-HS to appear as a DTE device, put the DIP shunt jumper in socket XW1B. For the LD485A-HS to appear as a DCE device, put the DIP shunt...

  • Page 8: Frame Ground/Signal Ground

    CHAPTER 3: Installation 3.1.2 F RAME ROUND IGNAL ROUND Jumper W7 ties signal ground to frame ground. The position is left open at the factory. If signal ground is to be connected to frame ground, solder a 100-ohm, 1/2-watt resistor in location W7. A wire jumper may also be used. Care must be taken to ensure that ground circulating currents are limited to acceptable levels.
  • Page 9 LD485A-HS and LD485A-HS Opto-Isolated T A T B R A R B Figure 1. Layout of the Printed Circuit Board.

  • Page 10: Cts Delay

    3.1.5 RS-485 D RIVER NABLE The LD485A-HS’s RS-485 driver can be set to be enabled one of three ways: by RS-232 control signals, by data, or constantly on. Driver Enabled by RS-232 Control Leads If your equipment raises CD or RTS, you can set the RS-485 driver to be enabled by one of these leads.

  • Page 11: Half-Duplex Turnaround Delay

    When jumper W15 is placed in the B-C position, the driver is enabled when data is received on the RS-232 port of the LD485A-HS. As soon as the first bit of the first character is received at the RS-232 port, the RS-485 driver is enabled and an internal timer is started.

  • Page 12: Normal/Loopback Operation

    Multipoint For multipoint applications, switch S2 should be in the “UNTERM” position on all the LD485A-HS devices in the network except for the two units at the extreme opposite locations on the line. The extreme opposite devices are the two devices that have the greatest cable length between them, which may not necessarily be the devices that are physically located the farthest apart.

  • Page 13: Dce Configuration/Dte Configuration

    LD485A-HS and LD485A-HS Opto-Isolated 3.2 DCE/DTE Configuration This section contains block diagrams (Figures 2 and 4) and jumper and switch settings (Tables 1 and 2) for DCE/DTE operation. For a detailed description of the jumpers and switches, see Section 3.1.
  • Page 14 CHAPTER 3: Installation Table 1. DCE Jumper Settings NOTE For additional information on the jumper requirements, see Section 3.1. FUNCTION JUMPER REQUIREMENTS 1. Configure RS-232 port as DCE XW1 in A position 2. Signal ground connected to frame ground •Connected W7 is IN (solder your own 100-ohm, 1/2-watt resistor in place) •Not connected...
  • Page 15 LD485A-HS and LD485A-HS Opto-Isolated Table 1. DCE Jumper Settings (continued) FUNCTION JUMPER REQUIREMENTS 5. Enable RS-485 driver a. RS-485 driver enabled by RS-232 control leads •by RTS W15 in A-B position and W9 in 0-ms position W9 in 10-ms position W9 in 30-ms position b.
  • Page 16 CHAPTER 3: Installation Table 1. DCE Jumper Settings (continued) FUNCTION JUMPER REQUIREMENTS 7. RS-485 interface terminated or unterminated •Terminated S2 in TERM position •Unterminated S2 in UNTERM position 8. Normal or loopback operation •Normal mode S1 in Normal position •Loopback mode S1 in Loopback position 9.
  • Page 17 LD485A-HS and LD485A-HS Opto-Isolated Figure 3. Line Bias. S2 shows the line termination when “Term” is selected. S3 shows line bias when “Bias” is selected.
  • Page 18 The delay settings for W9 apply only to the CTS output of the LD485A- HS. Since CTS is not used when the LD485A-HS is configured as a DTE device, placing jumper W9 in either the 0-, 10-, or 30-msec position will allow the CD input to enable the RS-485 driver.
  • Page 19 LD485A-HS and LD485A-HS Opto-Isolated Table 2. DTE Jumper Settings NOTE For additional information on the jumper requirements, see Section 3.1. FUNCTION JUMPER REQUIREMENTS 1. Configure RS-232 port as DTE XW1 in B position 2. Signal ground connected to frame ground •Connected...
  • Page 20 CHAPTER 3: Installation Table 2. DTE Jumper Settings (continued) FUNCTION JUMPER REQUIREMENTS b. RS-485 driver enabled by data W15 in B-C position and •Disable timeout delay W17 msec 0.15 c. RS-485 driver constantly enabled W9 in ON position 6. Half-duplex turnaround delay W8 in HALF position and •0-msec turnaround delay W16 in position A...

  • Page 21: Typical Applications

    RS-485 CD will ALWAYS be on. 3.3 Typical Applications This section describes some typical applications where the LD485A-HS might be used. The connections shown in the figures are for the RS-485 port. Figure 5 shows a typical point-to-point, 4-wire, full- or half-duplex connection with both LD485A-HSs terminated by setting switch S2 to the TERM position.
  • Page 22 CHAPTER 3: Installation LD485-HS LD485-HS RS-232 RS-232 DEVICE DEVICE TERMINATED TERMINATED Figure 5. Point-To-Point, 4-Wire (Full- or Half-Duplex). LD485-HS LD485-HS RS-232 RS-232 DEVICE DEVICE TERMINATED TERMINATED Figure 6. Point-to-Point, 2-Wire (Half-Duplex).
  • Page 23 (See Figures 7 and 8.) A resistor shown in the circuit indicates that the termination resistor has been selected via switch S2. Note that although Figures 7 and 8 show only four LD485A-HS devices networked together, up to 64 units can be connected in the manner shown...
  • Page 24 CHAPTER 3: Installation LD485-HS LD485-HS MASTER MASTER RS-232 RS-232 DEVICE DEVICE TERMINATED TERMINATED SUBORDINATE SUBORDINATE RS-232 RS-232 DEVICE DEVICE LD485-HS UNTERMINATED UNTERMINATED LD485-HS Figure 7. Multipoint, 4-Wire (Half- or Full-Duplex).
  • Page 25 LD485A-HS and LD485A-HS Opto-Isolated LD485-HS LD485-HS RS-232 RS-232 DEVICE DEVICE TERMINATED TERMINATED RS-232 RS-232 DEVICE DEVICE UNTERMINATED UNTERMINATED LD485-HS LD485-HS Figure 8. Multipoint, 2-Wire (Half-Duplex).
  • Page 26 “CLEAR” command. This command causes the remote PLC to resume data logging while waiting to be addressed again. Therefore, set each LD485A-HS for full-duplex operation (jumper W8 in the “FULL” position).
  • Page 27 7. Since all the remote PLC stations must be inactive until addressed, the RS-485 driver of each remote LD485A-HS must not be constantly enabled (W9 of each remote LD485A-HS must be set to a position other than ON). The remote PLCs are fairly far from the industrial controller in our example, so it would be wise to set the CTS Delay (jumper W9) for 10 msec.

  • Page 28: Appendix A: Pinning

    APPENDIX A: Pinning Appendix A: Pinning Table 3. RS-232 Interface (* Denotes pins that are used) Circuit Description Signal Type Direction Protective Ground Ground — Transmitted Data Data To DCE Receive Data Data From DCE Request To Send Control To DCE Clear To Send Control From DCE...
  • Page 29 LD485A-HS and LD485A-HS Opto-Isolated Table 3. RS-232 Interface (continued) (* Denotes pins that are used) Circuit Description Signal Type Direction Secondary Transmit Data To DCE Data Transmit Signal Timing From DCE Element Timing (DCE) Secondary Receive Data From DCE Data...
  • Page 30 Pin Name Description TXA and TXB Data received by the LD485A-HS at the RS-232 port is transmitted out of the unit over twisted-pair wires via these two outputs. The “TX” LED indicates the state of these two leads. When the TXA lead is positive with respect to the TXB lead ( a “zero”...
  • Page 31 LD485A-HS and LD485A-HS Opto-Isolated Quick Reference: User-Selectable Options Use this list as a quick-reference guide when you need to change the jumper settings. An asterisk (*) designates the factory-preset jumper settings. XW1A DCE* XW1B A-B* 4-wire 2-wire A-B* RTS/CD enabled Data enabled (Maximum speed is 64K.)
  • Page 32 LD485A-HS and LD485A-HS Opto-Isolated Turnaround delay (When W8 is in the B-C [2 wire] position, this is the time after the driver is disabled and before the receiver is enabled.) 0 msec 0.1 msec 1 msec 5 msec 35 msec NOTE: If the LD485A is configured Data Enabled (W15, position B-C) and 2-wire (W8 position B-C), then delays from W17 and W16 are cumulative.
  • Page 33 © Copyright 1999. Black Box Corporation. All rights reserved. 1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax 724-746-0746...

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