Synchronous Block Transfer with Basic module 1771-DB

[mulderm]

Hi everybody,


I want to pass data between the PLC5-processor (5/20) and the
Basic Module 1771-DB series A using synchronous Block Transfer.
I have an attachment file include with the rungs and the basic-
program for the Basic-module.
The problem is when the basic-program execute Call 6 (row 50)
nothings happen, call 6 means that this routine receive data
from the plc and the active bit from the Input Image Table
(I:013/1) must be '1'.
But I:013/1 is not '1' so the rung for the BTW is not true and
nothings happend.
When I toggle bit I:013/1, the rung is true and data is being
received.
The same is for the BTR.
Who can help me what the problem is?

Greetings,

mulderm

 

[msward]

I don't have your code but I use calls 3 and 2 to transfer data, remembering to set Block lengths first.
The PLC5 programe should have a one shot on the leading edge of the BTW check pending (bit I:xx/1)and in the BTW enable logic use this OSR with your signal that data is required to be sent to the basic module AND the BTW enable bit is not set (Nxx:xx/15) AND the BTR enable bit is not set.
Unlatch your data required to be sent signal with the BTW enable bit.

Hope this helps it took me days to get it working reliably with help from the FAQ on the rockwell site.

Mike

 

[mulderm]

Thank you MSward for your post,
Can you send me an example what your means
whith using RS-Logix rungs?
Do you use synchronous or asynchronous block transfer?
Greetings,

mulderm