What is a binary address used in ladder logic ?

Thread Starter

gbtbtbt

Joined Mar 18, 2020
55
Is a B3 address, another way of stating a seal in instruction? If not, why is the binary address used in a ladder logic program?
 

Papabravo

Joined Feb 24, 2006
13,559
Is a B3 address, another way of stating a seal in instruction? If not, why is the binary address used in a ladder logic program?
Seems like an ordinary label to me. What makes you think it is a binary address? Can you show us some context?
 

Thread Starter

gbtbtbt

Joined Mar 18, 2020
55
More of a general question. I came across a few ladder rungs that have a B3 address for output and input. In some situations, I had one B3 input with the same address reused in different strings, in addition with a seal in instruction with an input and output contact having same address.


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Papabravo

Joined Feb 24, 2006
13,559
It is just an address where you might decode them as I:3/0 as input bloc 3, bit 0. I don't know the specific details of I/O point or internal relay addressing. If needs to be understood by plant electricians I can assure it is not a binary or hexadecimal address.
 

MaxHeadRoom

Joined Jul 18, 2013
20,463
It appears to be the typical input memory register storage for an output function, IOW not like the O function that indicates a physical output.
Max.
 

Thread Starter

gbtbtbt

Joined Mar 18, 2020
55
Is the B3 addressing act another method of seal in instruction, but saving you an input bit? Is B3 addressing, used to save slot/bit memory?
 

Thread Starter

gbtbtbt

Joined Mar 18, 2020
55
I'm guessing that B3 is not a physical connection of input or output device, but used to simulate a relay. Is it possible to use more than one B3 addressing to save I/O bits? In problem number 4, am I able to use the B3 address and the same output addresses to simulate a seal in instruction multiple occasions?
 

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MaxHeadRoom

Joined Jul 18, 2013
20,463
That is what I pointed to in post #6, in a PLC ladder format, Individual internal register bits are used in the same manner as the physical ouputs, and used to record the final outcome of a rung in the same way, just that they only seen as status bits.
Allen-Bradley PLC uses the B# file where individual bits of the word are used for internal storage/status.
Max.
 
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Thread Starter

gbtbtbt

Joined Mar 18, 2020
55
Thank you for the help everyone. Max, your devotion to answering an abundance of questions is admirable. Thank you for the time you put in helping those like me understand the material.
 

MaxHeadRoom

Joined Jul 18, 2013
20,463
The B# register storage bit comes into its own to store a large/many conditions of for e.g. safety conditions an automatic machine which would be included in many rungs, when including the single storage status bit in the required rungs, this saves on repeatedly writing a rung with many functions and also saves on system memory.
Max.
 

GetDeviceInfo

Joined Jun 7, 2009
1,702
The B file is a simple designation for bit wise storage. Kind of like declaring your variable type. Any bit wise logic can be stored there. You could store that same bit in An array within bytewise files as well. Look at your data file, chances are you will see different data files serving the different data types. Each having its own prefix indicating its type. In Controllogix at least, you declare the depth of memory allocation, declare its type, and it’s created with the corresponding prefix.
 
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