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Allen-Bradley DH-485 User Manual

Allen-Bradley DH-485 User Manual

Communication interface
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DH 485
Communication Interface
(Cat. No. 1770 KF3)
User's Manual

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Summary of Contents for Allen-Bradley DH-485

  • Page 1 DH 485 Communication Interface (Cat. No. 1770 KF3) User’s Manual...
  • Page 2 Allen-Bradley Company cannot assume responsibility or liability for actual use based upon the illustrative uses and applications. No patent liability is assumed by Allen-Bradley Company with respect to use of information, circuits, equipment, or software described in this text.

  • Page 3: Table Of Contents

    Table of Contents Manual Overview ....... . Audience ......... . Related Publications .
  • Page 4 Table of Contents Specifications ........RS 232C Interface .

  • Page 5: Manual Overview

    1770-KF3 Audience Read this manual if you are installing and configuring a 1770-KF3 Interface Module for use with a DH-485 network. You should be familiar with: Allen-Bradley SLC 500 series of programmable controllers Allen-Bradley DH-485 networks...

  • Page 6: Product Overview

    The DH-485 Communication Interface module links host computers with the Allen-Bradley RS-485 Data Highway (DH-485). The module supports Interface the protocol required to act as a node on the DH-485 network, freeing the host computer from this task. Figure 1.1 The DH 485 Communication Interface (1770 KF3) Important: The DH-485 Communication Interface module (cat.

  • Page 7: The Dh 485 Network

    Chapter 1 Product Overview The DH 485 Network The DH-485 communication network allows devices on the plant floor to share information. Via the network, application programs can: monitor process and device parameters and status, including fault and alarm detection perform data acquisition...
  • Page 8 Chapter 1 Product Overview Table 1.A Protocol Applications Protocol Point to Point Multi Point Full duplex Half duplex A description of these protocols is given in the Data Highway/Data Highway Plus/DH-485 Protocol and Command Set Manual (publication 1770-6.5.16).

  • Page 9: Installing The Kf3

    Figure 2.1 shows the back panel of the KF3, including its two communication connectors. The connector labelled RS-232 Computer connects to the host computer via an RS-232C cable. The connector labelled DH-485 connects to the DH-485 network. Figure 2.1 KF3 Back Panel Fuses FUSES: 0.1A 250V...

  • Page 10: Dh 485 Cabling Considerations

    The shield reduces the effect of electromagnetic noise from the industrial environment. Belden #9842 cable is recommended. The pinouts for the KF3’s DH-485 connector are shown in Figure 2.2. Figure 2.2 KF3 Pinouts FUSES: 0.1A 250V...
  • Page 11 Chapter 2 Installing the KF3 Table 2.A Wire/Terminal Connections for Imtermediate Nodes For this Wire/Pair Connect this Wire To this Terminal Shield/Drain Non jacketed Terminal 2 - Shield Black/White Black Wire Cut back - No connection White Wire Terminal 3 (Signal Ground) Black/Red Black Wire Terminal 4 (Data A)
  • Page 12 KF3 is connected directly to the link coupler. In this topology, both the KF3 and the SLC 500 are end nodes. Construct a cable to attach the DH-485 connector on the back of the KF3 module to the link coupler. Figure 2.5 shows the connection for a point-to-point DH-485 application.
  • Page 13 1747-C11 cable the KF3 is connected to the network at one of the link couplers the DH-485 cable consists of three segments of cable daisy-chained to the link couplers and the KF3 The connection between the first node (the KF3) and the link coupler to the...
  • Page 14 Chapter 2 Installing the KF3 Figure 2.7 Connection for First Segment of a Multidrop Network Jumper to ground shield connector DH 485 Cable Jumper to terminate node 1770 KF3 on one end of the link Link coupler to first SLC 500 * The black wire of the white/black pair should be cut back (no connection).
  • Page 15 * The black wire of the white/black pair should be cut back (no connection). Installing the DH 485 Cable The DH-485 cable consists of a number of daisy-chained segments. The total length of the combined segments must not exceed 4,000 feet. Cut the cable segments long enough to route from one node to the next, allowing sufficient slack to prevent strain on the connectors.

  • Page 16: Rs 232C Cabling Considerations

    Chapter 2 Installing the KF3 RS 232C Cabling Cabling for the RS-232C connector of the KF3 will vary depending on your application. The pinouts for this connector are given in Table 2.B. Considerations Table 2.B RS 232C Connector Pinouts Signal Abbreviation Direction Pin No.
  • Page 17 Chapter 2 Installing the KF3 Use Belden #8723 (or equivalent) cable to construct a cable to connect the KF3 to a computer. Important: The length must not exceed 50 feet, and the cable shield must be connected to chassis ground (using Pin 1) at the KF3 end only. There are various cabling options depending on whether or not your application makes use of handshake signals, whether or not you are connecting to a 9-pin serial port for an IBM AT, and whether or not your...
  • Page 18 Chapter 2 Installing the KF3 If your computer requires active DSR and CTS signals, add jumpers to the computer connections as shown in Figures 2.13 and 2.14. Figure 2.13 Jumper Positions for DSR and CTS Lines (25 pin) Computer Shield TXD 2 3 RXD RXD 3...
  • Page 19 Chapter 2 Installing the KF3 If you are using handshake signals with your computer, use the connection shown in Figure 2.15 or 2.16. Figure 2.15 Connection to IBM Computer with Handshake Signals (25 pin) Computer Shield TXD 2 3 RXD RXD 3 2 TXD RTS 4...

  • Page 20: Modem Cabling Considerations

    Chapter 2 Installing the KF3 Modem Cabling The KF3 is connected to a modem via a direct 25-pin-to-25-pin cable, which you must construct using Belden #8723 (or equivalent) cable. Considerations Important: The length must not exceed 50 feet, and the cable shield must be connected to chassis ground (using Pin 1) at the KF3 end only.

  • Page 21: Voltage Selection

    Chapter 2 Installing the KF3 Auto-Answer: These modems have self-contained timeouts and tests, and can answer and hang up the phone automatically. The module has no means of controlling an auto-dial modem, but it can be used in conjunction with a separate auto-dialer. Voltage Selection CAUTION: The KF3 must be set to the correct voltage before it is powered up.

  • Page 22: Replacing Fuses

    Chapter 2 Installing the KF3 230V Operation Set the power select switch to “230V” as shown in Figure 2.19. Figure 2.19 Power Select Switch Set for 230V Operation FUSES: 0.1A 250V TYPE 5mm X 20MM CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE REPLACE ONLY WITH THE SAME TYPE Ë...

  • Page 23: Positioning The Kf3

    Chapter 2 Installing the KF3 Figure 2.20 Replacing Fuses Fuse Holder Fuse Fuse Holder Assembly Screwdriver Fuse Receptacle Positioning the KF3 The KF3 is intended to sit on a flat surface, such as a desk top or shelf. It has been designed for operation in both control room and plant floor environments.

  • Page 24: Configuring The Kf3

    Chapter Configuring the KF3 Configuration You configure the KF3’s communication parameters using the push buttons and displays located on the bottom of the module. The module saves them in nonvolatile memory. Factory default settings (shown in Table 3.B) should be adequate for most industrial usages. Important: Verify that all parameter settings are correct for your purposes before connecting the KF3 to your network.
  • Page 25 Chapter 3 Configuring the KF3 Displays Figure 3.1 shows the configuration displays on the bottom of the module. The left display (one digit) shows the number of the communication parameter being configured. The right display (two digits) shows the current setting for that parameter. Communication parameters are configured in two menus, a main menu, for basic parameters, and a submenu, for more advanced parameters.
  • Page 26 Chapter 3 Configuring the KF3 Configuration Steps Entering Configuration Mode Press the View button to enter configuration mode. The first parameter number will be displayed on the left, with its current setting on the right. The KF3 continues to communicate while in configuration mode. Changes in configuration do not affect operation until they are saved and the module returns to run mode.
  • Page 27 Chapter 3 Configuring the KF3 Figure 3.2 Successful Save Display If the save is not successful, your KF3 is malfunctioning. The left display will show hardware fault number 6 (see Table 5.B) and the front panel fault indicator will light. If this happens, contact your A-B representative.

  • Page 28: Basic Communication Parameters

    The basic communication parameters are divided into two groups: those that control the link with the DH-485 network, and those that control the RS-232C link with the computer. The parameter number is shown in the left display, the current setting in the two right displays.
  • Page 29 Chapter 3 Configuring the KF3 Table 3.B Basic Configuration Parameters (continued) Parameter Number Parameter Description Factory Default RS 232C Parameters RS 232C Baud Rate Baud rate of the RS 232C link between the host computer and the KF3. 9600 baud (96). The host computer and KF3 must be set to the same baud rate.

  • Page 30: Advanced Communication Parameters

    Chapter 3 Configuring the KF3 Advanced Communication The advanced communication parameters are located in the Submenu. When parameter 9, the Submenu entry parameter, is shown on the left Parameters display, the Data display on the right will show dashes. Press the Data button to enter the Submenu and display the submenu parameter numbers.
  • Page 31 Chapter 3 Configuring the KF3 Table 3.C Submenu Configuration Parameters Parameter Number Parameter Description Factory Default Maximum Token The node address of the highest numbered master station on the Address (31). Holder DH 485 link. The valid range for Maximum Token Holder is 01 31. If all stations have consecutive addresses, this parameter should be set to the address of the highest numbered master station on the link.
  • Page 32 Chapter 3 Configuring the KF3 Table 3.C Submenu Configuration Parameters Parameter Number Parameter Description Factory Default CTS to Transmit Delay The delay between the CTS signal and the start of transmission by the No delay (00). KF3 (half duplex only). The delay is from 0 seconds to 0.99 seconds, in 10 ms (0.01 second) increments.

  • Page 33: Verifying Your Configuration Parameters

    When you connect the module to your network and turn it on, the displays will cycle through the numbers 1-3 and then turn off. If your DH-485 parameters are correctly configured, the DH-485 Activity LED on the front of the module will light up. If the Fault LED lights up instead, check your station address, as stated in Parameter Number 0, Table 3.B.

  • Page 34: Communicating With The Kf3

    In full-duplex mode, the destination address in a packet sent from the host computer to the KF3 is the address of the DH-485 network node for which the packet is intended. The source address in packets received by the host...
  • Page 35 Because the KF3 acts as a slave on a DF1 half-duplex network, the half-duplex master’s access to the DH-485 nodes is indirect: i.e., the destination address and the station address are generally different.
  • Page 36 Remote Mode The valid range of slave addresses on a half-duplex network is 000-376 octal – a total of 255 stations. The valid range of addresses on a DH-485 network is 00-31 decimal. In order to make these two systems compatible, two special submenu configuration options have been included in the KF3 (see Table 3.C).
  • Page 37 Chapter 4 Communicating with the KF3 Table 4.A Half Duplex Remote Address Conversion Table DH 485 Node Half Duplex DF1 Address (Octal) Address Address (Decimal) Group 00 Group 01 Group 02 Group 03 Group 04 Group 05 Group 06 Group 07 Illegal...
  • Page 38 Chapter 4 Communicating with the KF3 Example: Remote Mode Addressing on a Multidrop Network This example uses the 1771-KGM as the half-duplex master in a multidrop configuration. Each of the KF3s is set to half-duplex remote mode, and has the half-duplex Master Address set to the address of the 1771-KGM (010).

  • Page 39: Communicating With Dh 485 Master Devices

    SLC 500 SLC 500 Communicating with The KF3 operates as a token-passing master on the DH-485 network. It can communicate with other DH-485 master stations (such as the SLC 500 DH 485 Master Devices series of programmable controllers) and with DH-485 slave devices.
  • Page 40 Communicating with the KF3 Slave Packet Formats To invoke DH-485 link layer services, a special PCCC CMD byte is used to support the addition of link-specific information to the packet. Setting the CMD byte = 09 indicates that the packet contains extended link information.
  • Page 41 Chapter 4 Communicating with the KF3 NAK, Bad LSAP (SRD reply). This link error is returned when the KF3 receives a NAK, Bad LSAP message from the destination station in response to an SRD request. This indicates that the LSAP you are trying to send the SRD request to is invalid for that destination device.

  • Page 42: Communicating With A Modem

    Chapter 4 Communicating with the KF3 Reply Format, SRD Request The format of a reply to an SRD request is shown in Figure 4.5: the CMD byte will have the reply bit set the link type will be set to SRD Request the link status will indicate success or failure the LSAP of the slave device (SLSAP) will be included if the request was successful, the data will be included.
  • Page 43 Chapter 4 Communicating with the KF3 This handshaking is necessary to guarantee access to the phone line. If the handshaking protocol is defeated by improper selection of modem options or by jumpers at the connectors, the modem may still answer a call. But if the connection is lost, the modem will not hang up.

  • Page 44: Troubleshooting The Kf3

    Chapter Troubleshooting the KF3 Interpreting the Front Panel There are four LEDs on the front panel of the KF3. These indicators can help you in diagnosing problems with the module’s installation and LEDs operation. Table 5.A LED Indicators LED Indicator Description Power This indicator is lit (green) when the module is plugged in and turned on.

  • Page 45: Interpreting The Numeric Displays

    Contact your A-B representative. When you connect the module to your network and turn it on, the displays will cycle through the numbers 1-3 and then turn off. If your DH-485 parameters are correctly configured, the DH-485 Activity LED on the front of the module will light up.
  • Page 46 Chapter 5 Troubleshooting the KF3 Once you initiate active communication on the DF1 link, the RS-232 Activity LED will light up. If this fails to happen, check your RS-232C parameters (Table 3.B, Parameters 3-8). If you are unable to save new configurations successfully, the left display will display hardware fault 6, and the Fault LED on the front will light up.

  • Page 47: Specifications

    Appendix Specifications RS 232C Interface Start bits Data bits Parity None, Even Stop bits Baud rates 300, 600, 1200, 2400, 4800, 9600, 19200 Connector DB 25P (male) Output RS 232C DH 485 Interface Start bits Data bits Parity Even Stop bits Baud rates 300, 1200, 2400, 4800, 9600, 19200 KF3 connector...

  • Page 48: Physical

    Appendix A Specifications Physical Dimensions 9.5" (24.1 cm) wide x 7.1" (18.0 cm) long x 2.4" (6.1 cm) high Weight 2 lbs. (.9 kg) approx. Environmental Operating temperature 0 C to 60 C (32 F to 165 F) Storage temperature 40 C to 85 C ( 40 F to 210 F) Operating humidity 5% to 95% (noncondensing)

  • Page 49: Diagnostic Command Support

    Appendix Diagnostic Command Support The KF3 will interpret and respond to the following diagnostic commands: Table B.A KF3 Diagnostic Commands Description Command Byte Function Code (hex) Diagnostic Loop Diagnostic Read Counters Diagnostic Status Reset Diagnostic Counters Read Link Parameters Set Link Parameters Diagnostic Loop You can use this command to check the integrity of the transmissions over the communication link.

  • Page 50: Diagnostic Read

    Appendix B Diagnostic Command Support Diagnostic Read This command reads the diagnostic counters from the KF3. The format of these counters is given below. Note that the address and size fields can have any value (but they must be included). Figure B.3 Diagnostic Read Command Format 1 byte...
  • Page 51 Appendix B Diagnostic Command Support Table B.B contains the diagnostic read reply values for the KF3: Table B.B Diagnostic Read Reply Values Byte Description Total DH 485 packets received, low byte Total DH 485 packets received, high byte Total DH 485 packets transmitted, low byte Total DH 485 packets transmitted, high byte Number of DH 485 retries Number of DH 485 packets where the retry limit was exceeded...

  • Page 52: Diagnostic Status

    Node Table would look like this: Diagnostic Status This command requests a block of status information from a DH-485 device. The reply contains the information in its DATA field. The status information varies from device to device. The KF3’s status block is given below.

  • Page 53: Diagnostic Counter Reset

    Appendix B Diagnostic Command Support Table B.C Diagnostic Status Reply for KF3 Byte Description Status Reply (hex) Mode/Status byte 00 (No Modes) Interface/Processor Type Bits 0 3: Interface type (E = Extended) Bits 4 7: Processor type (F = Computer) Extended Interface Type Not Used Series/Revision...

  • Page 54: Read Link Parameters

    Appendix B Diagnostic Command Support Read Link Parameters This command reads the link parameters defined for the KF3. Currently there is only one link parameter: Maximum Token Holder Address. This command returns the value for this parameter in the DATA byte. Figure B.9 Read Link Parameters Command Format 1 byte...
  • Page 55 Index Numbers configuration display and push buttons, 115V operation, 2 13 configuration mode, 1747 C11 cable, configuring the KF3, 1771 KGM, connection 230V operation, 2 14 between a KF3 and a modem, 2 12 between two intermediate nodes, for first segment of a multidrop network, for the last segment of a multidrop active node table, network,...
  • Page 56 Index I–2 diagnostic counter reset, group number, command format, group numbers, reply format, diagnostic loop, command format, reply format, half duplex, diagnostic read, master, command format, half duplex DF1, reply format, half duplex master, station address, reply values, handshake signals, 2 11 diagnostic status, command format,...
  • Page 57 Index I–3 link type field, local mode, read link parameters, command format, reply format, receive data (RXD), main menu, related products, manual overview, remote mode, maximum cable length, 2 12 addressing, maximum token holder, replacing fuses, 2 14 maximum token holder address, reply format diagnostic counter reset, modem,...
  • Page 58 Index I–4 submenu, TXD, configuration parameters, indicator, successful save display, unable to save, temperature operating, verifying your configuration parameters, storage, 3 10 terminating, view button, three wire connection, to IBM computer voltage selection, 2 13 25 pin, 9 pin, timeout, weight, token hold factor, token passing,...
  • Page 59 As a subsidiary of Rockwell International, one of the world’s largest technology companies — Allen-Bradley meets today’s challenges of industrial automation with over 85 years of practical plant-floor experience. More than 13,000 employees throughout the world design, manufacture and apply a wide range of control and automation products and supporting services to help our customers continuously improve quality, productivity and time to market.

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