Edwards 970522 Tech Bulletin

Edwards Signaling Fieldstone Court CT 06410 699 3300 203 699 3108 Bulletin 970522 Category PLC Activation 9 1999 Centers Activating Messages using a Dry Contact Closure Edwards Message Center is capable of displaying messages using an ASCII Text string technical bulletin will demonstrate how to activate messages previously loaded into your Message Center utilizing a Dry Contact Closure This method is very similar to Technical 970521 in that a PLC is used to send an ASCII Text String to the Message Center The needs to be capable of sending this string to either an RS232 or RS485 output on the PLC text string must also be in the proper format otherwise the message will not be displayed Any Ladder Logic Programmer will understand these basic instructions and will be able to these commands into more complex Ladder Logic Functions I Application Example end user wishes to monitor several limit switches When a limit switch is activated they wish to a text message on an Edwards Message Center This can be accomplished using a PLC is capable of outputting an ASCII text string The PLC can then be programmed to output the Command code to turn on a message like Low Level in Tank 12 Also an audible or signal could be activated at the same time if the PLC has Relay outputs This is ideal for attention to an important message that is being displayed on the Edwards Message is a basic way to operate a Message Center using Dry Contact Inputs Once again an programmer will be able to program their PLC for this type of operation and will be to perform more complicated operations Also the desired messages must be programmed of time into the Edwards Message Center II Hardware Connections type of contact Momentary or Maintained will need to be determined by the input of the PLC in use Also the PLC Software must be capable of sending an ASCII String to an RS232 Serial Port For single Message Center operation use an adapter and through RS 232 cable as shown in diagram 1 For multiple Message Center or RS485 follow the wiring employed in diagram 2 Another use of the PLC is to use Output cards control a signaling device when a message is being displayed diagram 3 An example may be have a horn sound or a light flash to alert personnel that an important message is being Generally PLC output cards have the option of either a relay output or a source voltage option can be used when Edwards Process Control Signals are utilized Bulletin 970522 1 of 5 No ferrite end towards Message Center foot 6 conductor RS 232 cable foot 6 conductor RS 232 cable Pin D Sub to 6 pos RJ11 adapter foot 9 pin to 9pin type A9 RS232 cable Set internal message center jumper to RS232 1 No Termination ferrite end towards Message Center foot 4 conductor RS 485 cable foot 4 conductor RS 485 cable network adapter foot spool of RS485 cable box w 2 EOL terminators foot 9 pin to 9 pin type A9 RS232 cable Set internal message center jumper to RS485 2 Bulletin 970522 2 of 5 A RS232 Cable from PLC to the Edwards Message Center PLC A Basic PLC consists of the CPU Input and Output Cards C Contact Device PLC have different input requirements this contact device may be Normally Open D Edwards Audible Signal See your Edwards Catalog E Edwards Visual Signal See your Edwards Catalog III Software Configuration 3 configure any software for communications with the Message Center the following parameters need to established by the user The Message Center will not receive any data transmitted faster than 9600 Bits Bits IV Message Center Setup must be loaded into the Message Center using any of the 81 valid File labels Refer to your Control Programming Instructions or Technical Bulletin 970520 for information on loading into your Edwards Message Center V Text String Format Bulletin 970522 3 of 5 an ASCII text string to a Message Center can easily activate any message saved in the Message memory Listed below is a sample string that instructs an Edward Message Center to display a message The Message Center serial address in this example is 01 Each message string should begin with five NUL 00h characters for auto baud detect of serial sent to the Message Center Messages should follow the Special Function Text Format outlined example 1 A B C D E I F G H Value Code Address Code Functions Label Sequence Order or S or 53h Protection or L or 4Ch File Label B etc 42h etc consecutive NUL for sync auto baud detect of the of Header character Type Code for All Signs in network Byte ASCII Hex Sign Address see note 1 of Text character code E Write Special Functions to the sign Run Sequence 54h All subsequent Text File Labels in the run will run according to their associated times 53h All subsequent Text File Labels in the Run will run in order regardless of each file run time 55h Unlocked This allows the Run Sequence to be from the Handheld Remote 4Ch Locked The Run Sequence is inaccessible from Handheld Remote Files to be activated More than one file can be This also determines the run order EOT end of transmission character Must follow the of every message string The serial address of the Message Center is represented by two ASCII digits as a number 00 to FF 0 to 255 If 00 is the desired serial address the two byte ASCII would be 30h for the first digit and 30h for the second digit It is important to Bulletin 970522 4 of 5 to treat the serial address as a two digit code All Message Centers on the network will to the string when the serial address is 00 VI Sample Strings Action Text File A Text File B Text File C Text Files A B C Required The Run Sequence Order is determined by the order of the File Labels as entered into the text VII Additional Support questions please call our Technical Support 203 699 3300 or visit our website www edwards Additional codes are available for controlling message center text strings in our Protocol available from your local Edwards Signaling representative Bulletin 970522 5 of 5