plc notes march 23th

plc notes march 23th - data table addres remote plcs memory...

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Sheet1 Page 1 message intrstuon (MSG) is used to transfer data between PLC's IT is an output instructuin it must be triggered- usually a timer done bit used to trigger it MSG instrucitons take about 500ms to execute during this, the plc scan is paused the msg instructio needs a control file - R6 is used for contu can define another integer file N# (9-9999) as the control file for the msg isntruction control file stores status of the msg instruciton - successful, comm failure DN, etc. .. msg transmits or receives words, not bits - no addresses to the bit level (no slashes) up to 1000 words can be transferred by one msg instruction must be in sequence (eg. N7:0 to N7:999) PLC-5 MSG instruction control file parameter N9:0 setup screen --> new window communication command PLC-5 typed read or write read - copies data from remote plcs memory to your plcs memory write - copies data from your plcs memory to remote plcs memory data table address - your plcs memory address size in elements - number of word being transferred
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Unformatted text preview: data table addres - remote plcs memory addres (eg T4:-.PRE local station addres - plc address in octal multiple msg instruciton can exist in the same prgram - they should be triggered at differ times one msg instruction can only communicate with one plc at a time. to communicate with 5 plcs you will need 5 message instructions eg. write a plc program that read N7:0 from another plc-5 (address - 30) periodically (30 seocnds) and stores it in N7:10 on your plc-5. which a switch on your plc is triggered, take the last value stored in N7:10, add one to it, and write it to the other PLC-5, in N7:5. the result should be that N7:5 is the remote plc will show how many times tje switch ha has been striggered on the original PLC plus whatever is stored in N7:0 of the remote plc within 30 seconds, the switch could be toggled multiple times the total no. of toggles with the 30 secds need to be sent to N7:5 on the remote plc...
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This note was uploaded on 04/08/2011 for the course ENGR 3 taught by Professor Szabados during the Spring '11 term at McMaster University.

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