Synchronous Block Transfer with basic module

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

BTs are sometimes tricky

Try both of these links, they may help you out.

A-B Knowledge base search.

Specific article on synchronus BTs

Keep on trying, you will make it.

I recall running in to this problem a few years ago. You program the Block Transfers just like the book says to and they work for a while and then stop.

I think there is a bug in the DB module causing this. I tried several different cards, old and new, and could not fix it. I would check with your AB rep.

I gave you some hints on the other board ... did they help? ...

post on another forum

Hello Ron,

I have making the 2 rungs like the example on page 85 from
the Basic module manual 1771-db/b with other adresses.
Maybe you´re right and are the active bits (input image byte)
not available for the series A module.
I want to make handshaking to enable the block transfers only when
the basic module send this.
Is there another way to do this?, i want to use the series A module.
Can I use the call 6 and call 7 for this?

Greetings,

mulderm