TM 5-3895-374-24-2 CONNECTION TO THE A-701 DIGITAL READOUT The Dwyer A-701 Digital Readout  provides  a  3  ½    digit LED   display   of   the   relative   or   actual   pressure   being sensed   by   the   Series   604   Transmitter.      The   A-701 operates  directly  from  standard  AC  line  voltage.    It  is suggested that you familiarize yourself in general with the A-701 by reading the instruction bulletin supplied with the readout.      A   printed   circuit   board   edge   connector   is supplied    with    the    A-701    to    facilitate    the    electrical connections required.  The standard A-701 is supplied to read  zero  at  4  milliamps  and  100.0  at  20  milliamps. Thus, the standard digital display represents percentage of  full  range  pressure  being  sensed  by  the  transmitter. However,  the  A-701  can  also  be  ranged  in  the  field  to any engineering units required.  To re4ange the display, snap out the front panel and use a small screwdriver to rotate the screw adjustment "F" at the lower left corner of the LED circuit board until the intended reading at a loop current  of  20mA  is  obtained.    With  4  mA  loop  current, check  the  zero  setting.    If  necessary,  rotate  the  screw adjustment "O" at the lower right comer of the LED circuit board until the display reads zero.  Since there is some interaction   between   these   controls,   recheck   and   re- adjust    both    settings    until    consistent    operation    is achieved. Refer    to    Figures    E    and    F    for    connection    of    the transmitter  cable  to  the  A-701  edge  connector.    Once these connections have been made, connect the AC line to  the  appropriate  pins  on  the  edge  connector.    The installation is completed by the installation of the desired decimal point selection jumper as indicated in Figure G. Use  care  in  identifying  the  appropriate  edge  connector pins and solder each connection carefully.  Use insulated sleeving to cover the completed connections, particularly the  AC  line  connections.    Note  that  the  AC  line  power required  is  minimal  and  lighter  gage  stranded  wire  is recommended for the AC line connection.  Be careful not to  bend  unused  lugs  on  the  edge  connector  to  avoid shorting  adjacent  connections.    Observe  the  keyway  in the   circuit   board   and   on   the   edge   connector   when installing the connector to the circuit board.  Refer to the A-701  instruction  manual  for  mounting  and  dimension information. A-701 Pin Designations NOTE:   Pin  designations  for  the  edge  connector  are the same as above when viewed from solder lug  side.    Designations  are  also  molded  into connector body. FIGURE E TABLE OF CONNECTIONS FROM A-701 TO SERIES 604 TRANSMITTER Pin 15: AC Line   115/230 VAC, 50-60 Hz Pin S: AC Line Pin 2: To negative terminal of Transmitter Pin 9: To positive terminal of Transmitter Pin 10 To Pin K: Jumper Wire 115 WC STANDARD, REFER TO FACTORY FOR 230 VAC. FIGURE F DECIMAL POINT SELECTION No Jumper for 1999 Pin L to Pin N for 199.9 Pin M to Pin N for 19.99 Pin P to Pin N for 1.999 FIGURE G MULTIPLE RECEIVER INSTALLATION An    advantage    of    the    standard    4-20mA    output    signal provided by the Series 604 Transmitter is that any number of receivers can be connected in Series in the current loop. Thus, an A-701 Digital Readout Accessory, an analog panel meter, a  chart  recorder,  process  controlling  equipment,  (or any    combination    of    these    devices)    can    be    operated simultaneously.    It  is  only  necessary  that  these  devices  all be  equipped  with  a  standard  4-20mA  input  and  that  F  per polarity  of  the  input  connections  be  observed  when  insert the  device  in  the  current  loop.     If   any   of   the   receiving devices   displays   a   negative   or   downscale   reading,   this indicates that the signal input leads are reversed. MAINTENANCE Upon final installation of the Series 604 Transmitter and the companion receiver, including the A-701 Digital Readout, no routine maintenance is required.  A periodic check of system calibration  is  recommended.    The  Series  604  Differential Pressure Transmitter is not field serviceable and should be returned  to  the  factory  if  service  is  required.    The  A-701 Digital  Readout  should  be  returned  to  the  manufacturer  if service is required.  Refer to the A-701 instruction sheet. (page 3-712)