INSTRUCTION MANUAL MD9 Multidrop Interface Revision: 5/03 C o p y r i g h t ( c ) 1 9 8 7 - 2 0 0 3 C a m p b e l l S c i e n t i f i c , I n c .
Warranty and Assistance The MD9 MULTIDROP INTERFACE is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
MD9 Multidrop Interface Table of Contents PDF viewers note: These page numbers refer to the printed version of this document. Use the Adobe Acrobat® bookmarks tab for links to specific sections. 1. Introduction.................................................................1 2. System Description ....................................................1 3. Software and Datalogger Compatibility ....................3 4. ID and Baud Rate Selection .......................................3 5.
MD9 Multidrop Interface Table of Contents 4-1 ID Switch and Baud Rate Selection Jumpers........................................... 4 6-1 Telephone to MD9 Conversion................................................................ 6 B-1 Break/Address Timing Diagram.......................................................... B-1 This is a blank page.
MD9 Multidrop Interface 1. Introduction The MD9 Multidrop Interface functions as a direct wire link between a computer and a Campbell Scientific datalogger via coax cable. MD9s may be networked thereby permitting a computer to address and communicate with up to 254 dataloggers. Total coax length may be up to 3 miles when fewer dataloggers are used.
MD9 Multidrop Interface The MD9 at the computer is connected to one or more other MD9s with coax cable terminated with BNC connectors. Refer to Appendix A for cable specifications and source references. The MD9 at the datalogger is connected via an SC12 cable (supplied with the MD9) and is powered from the datalogger SERIAL I/O port. Each MD9 includes a BNC "T" connector to allow for coax in/ coax out.
MD9 Multidrop Interface FIGURE 2-1. System Description 3. Software and Datalogger Compatibility PC208 Software Index #5348-00 or higher is required for use with MD9s. Customers using older software may purchase a software update for a nominal charge by contacting Campbell Scientific. The following dataloggers may be used in an MD9 network.
MD9 Multidrop Interface TABLE 4-1. ID Settings for MD9 Connected to Computer Software Used ID Dos PC208 (GraphTerm, Telcom, and PC208E) Windows PC208W (Tcom) 1 - 254 255 NOTE An MD9 with the ID set to 255 can be used with the DOS PC208 by adding a pound sign (#) to the end of the base MD9 dialing path in the PC208 station file. This is useful if PC208 and PC208W must be used on the same MD9 network. NOTE Address 255 is also used when the MD9 is connected to a telephone modem (Section 6).
MD9 Multidrop Interface 35 MD9s @ 0.2 db 5,000 ft. @ 0.6 db/ 100 ft. Coax terminator pair 7 db (including MD9 at PC) 30 db 6 db Total Signal Loss 43 db 6. Telephone to MD9 Network It is possible to access an MD9 network via telephone when the network is miles from the PC. See Figure 6-1. A Campbell Scientific Model COM200 Telephone Modem is used in conjunction with a Model PS512M 12 and 5 Volt Charging Regulator to communicate with an MD9.
MD9 Multidrop Interface COM200 The null modem on the PS512M has two 9-pin connectors. The SC12 cable from the COM200 is connected to either connector and the SC12 from the MD9 is connected to the other. FIGURE 6-1. Telephone to MD9 Conversion 7. Operation Communication between the computer and a datalogger is initiated and controlled by the computer. The MD9 at the computer is activated when Pin 20, Data Terminal Ready (DTR), is pulled high on the computer's I/O port.
MD9 Multidrop Interface now complete. The computer can now send several carriage returns which permits the datalogger to synchronize at the same baud rate. Once the datalogger baud rate has been synchronized, data retrieval, data monitoring and re-programming of the datalogger can be carried out. To terminate communications with a datalogger, use the E command (followed by a carriage return) listed in the datalogger instruction manual.
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Appendix A. Cable Specifications and Source References Belden 1505A: Conductor: 20 AWG solid copper (.032” ∅) Jacket Material: PVC Jacket O.D.: .235 Shield: Braided tinned copper (100% coverage) Resistance: 10Ω/1000’ Capacitance: 16.2pf/ft. Impedance: 75 Ohms Attenuation at 1 MHz: 0.29 db/100’ Belden Wire and Cable P.O.
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Appendix B. Break/Address Timing A BREAK consists of continuous spacing for time greater than 10 times the inverse of BR (baud rate). The BREAK is followed by a marking period and single byte ADDRESS. The marking time must be greater than one times the inverse of BR and the marking time and ADDRESS must be completed within 100 msec. This is to say that a 9600 baud, the BREAK must be greater than 1.1 m sec followed by marking for 105 usec.
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Appendix C. Setting the Station ID Each MD9, including the one in the MD9 base station, must have a unique Station ID. Following is a list of all possible Station IDs with the corresponding setting of the dip switches. Here, 1 represents open and 0 is closed. When a station is configured for phone to MD9, PC208 DOS software cannot recognize an MD9 address greater than 127.
Appendix C.
Appendix D. SC532A The SC532A differs from the SC532 in three ways: 1. 2. 3. Provides 12 V on PERIPHERAL Port pin 8 “PROGRAM” mode Jack on SC532A POWER input The SC532A supplies 12 VDC via PERIPHERAL connector pin 8 for the purpose of powering 12 V peripherals. The SC532A’s internal jumper selects “SC532” or “PROG” mode. For the MD9 leave the jumper in the factory default position of “SC532.” “PROG” is a special mode for satellite transmitters only.
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Campbell Scientific Companies Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah 84321 UNITED STATES www.campbellsci.com info@campbellsci.com Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA www.csafrica.co.za sales@csafrica.co.za Campbell Scientific Australia Pty. Ltd. (CSA) PO Box 444 Thuringowa Central QLD 4812 AUSTRALIA www.campbellsci.com.au info@campbellsci.com.au Campbell Scientific do Brazil Ltda.
