PLC 5/250 MSG Instruction

sparky64

Member
Join Date
May 2003
Location
Newcastle upon Tyne
Posts
127
I'm using MSG Instructions to read / write 30 words of data between a PLC5/250 and an SLC5/04.

My MSG Instruction is scanned on condition of an OSR Instruction.

Can someone tell me, if the "MSG Instruction" is capable of transfering the required 30 words of data in 1 program scan.



Cheers

Sparky :)
 
when the rung goes true the message will then be pending the message is not sent till the end of the scan.

If you look in SLC instruction set help in the help menu of RSlogix 500 it give you a break down of the MSG instruction including max numbers of files that can be sent it varies for diffrent file types but 30 should be ok as long as there not Strings..

Jezz
 
Depends

The message instruction in the ladder code merely initiates action in the Resource Manager module, which handles the communication and data transfer. Once initiated, the Resource Manager performs the transfer asynchronously to the program scan running on the Processor module.

So completion relative to program scan depends on the amount of data transferred and the length of your program scan, posssibly with some minor influence from whether the data is in the Resource Manager data table or the Processor's.
 

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