Allen Bradley Plc Slot Numbering

Backplane current, chassis/slot max @ 3.3V DC 4 A/4 A Backplane current, chassis/slot max @ 5.1V DC 10 A/6 A 15 A/6 A Backplane current, chassis/slot max @ 24V DC 2 A/2 A 2.8 A/2.8 A Power dissipation, max 3.7 W 4.1 W 4.4 W 4.5 W 5.0 W Isolation voltage Determined by installed power supply and modules Slots 4757 10 Mounting method Horizontal only. The slot numbering for Compact I/O modules always goes left-to-right, no matter if you're using a R/L or R/R expansion cable. 1769-L32E Slot 0 1769-IQ16 Slot 1 1769-IQ16 Slot 2 1769-IQ16 Slot 3 1769-PA4 (no slot number) 1769-IQ16 Slot 4 1769-OW16 Slot 5 1769-OW16 Slot 6 1769-OW16 Slot 7 1769-Expansion cable (no slot number) 1769-IF8 Slot 8. Allen Bradley 1746-A10 SLC500 10-Slot PLC Rack With 2x Output & 1x Input Modules. EBay item number: 89. Seller assumes all responsibility for this listing. I am doing my first project for a compact logix 5370 L1. This controller has 16 embedded discreet imputs, iin 2 groupd of 8 and 16 embedded outputs, in 2 groups of 8 Is the correct desgination for each input Slot 1 0-7, Slot 1 8-15? I don't have an example drawing to look at for the L1 and I am on the fast track to get this done.

Help Contents

Introduction

There are two distinct ranges of Allen Bradley PLC Devices:

Model Types	Summary
SLC-500, MicroLogix, PLC-5.	These models are configured using ladder logic and store data in files. Tags in Fernhill SCADA are mapped to locations in the data files. The File Data Address Format defines which location in the PLC is mapped to a Fernhill SCADA Tag. Fernhill SCADA uses this tag format when the PLCType Configuration Property is set to 0 (Micrologix, SLC and PLC-5).
ControlLogix, CompactLogix.	These models implement the IEC 61131-3 standard and each data item is assigned a unique variable name. Tags in Fernhill SCADA are mapped to variables in the PLC program. The Variable Reference Format defines which variable in the PLC is mapped to a Fernhill SCADA Tag. Fernhill SCADA uses this tag format when the PLCType Configuration Property is set to 1 (ControlLogix or CompactLogix).

File Data Address Format

This File Data Address Format is used with MicroLogix, SLC and PLC-5 range of PLC Devices.

The File Data Address Format is a string that defines the location of data in a file based Allen Bradley PLC. The format of the string is:

Xf:e.w/b

Where:

X is the file type.
f is the optional file number.
e is the element number.
w is the optional word offset.
b is the optional bit offset.

File Type

Data in Allen Bradley PLC Devices is stored in files. For example there are separate files for Inputs, Outputs, Status Bits, Timers, Counter, Integers and so on. Some file types are fixed, for example there can only be one file each for Inputs, Outputs and Status Bits. Other files are more flexible, for example there can be multiple Integer files.

File	Type	Notes
O	Outputs	If used, the File Number must be 0. The Element Number sets the I/O slot. The Word Offset sets the word offset within the I/O slot. The Bit Offset sets the bit number (0-15).
I	Inputs	If used, the File Number must be 1. The Element Number sets the I/O slot. The Word Offset sets the word offset within the I/O slot. The Bit Offset sets the bit number (0-15).
S	Status	If used, the File Number must be 2. The Element Number sets the status word. The Bit Offset sets the bit number (0-15).
B	Bit	The File Number sets which bit file to use (3, 9-255). If not used, the File Number is 3. The Element Number sets the word. The Bit Offset sets the bit number (0-15).
T	Timer	The File Number sets which timer file to use (4, 9-255). If not used, the File Number is 4. The Element Number sets the timer index. The Word Offset sets the word offset within the timer (0-2). The Bit Offset sets the bit number (0-15).
C	Counter	The File Number sets which counter file to use (5, 9-255). If not used, the File Number is 5. The Element Number sets the counter index. The Word Offset sets the word offset within the counter (0-2). The Bit Offset sets the bit number (0-15).
R	Control	The File Number sets which control file to use (6, 9-255). If not used, the File Number is 6. The Element Number sets the control index. The Word Offset sets the word offset within the control (0-2). The Bit Offset sets the bit number (0-15).
I	Integer	The File Number sets which integer file to use (7, 9-255). If not used, the File Number is 7. The Element Number sets the word. The Bit Offset sets the bit number (0-15).
F	Float	The File Number sets which float file to use (8-255). If not used, the File Number is 8. The Element Number sets the float index.
ST	String	The File Number sets the which string file to use (9-255). The Element Number sets the string index. The Word Offset sets the word offset within the string (0-41).

File Number

In an Allen Bradley PLC, data is organized as files. The File Number is optional and, if included, sets which file to access. If the File Number is not included the file number is implied by the File Type. All PLC Devices have a predefined set of files as follows:

File	Type
0	Outputs
1	Inputs
2	Status
3	Bit
4	Timer
5	Counter
6	Control
7	Integer

Notes:

On a MicroLogix 1000 PLC no additional files can be defined.
On a MicroLogix 1200 PLC, SLC 5/01 CPU, or SLC 5/02 CPU file 8 is reserved. Additional file numbers 9 to 255 are user defined.
On a other PLC types file 8 is a Float file. Additional file numbers 9 to 255 are user defined.

Element Number

The Element Number sets which element of the file to access.

For Input and Output files, the Element Number indicates which I/O slot to access. An I/O slot may consist of 1 word, or multiple words depending on the type of I/O configured.

For other file types, the Element Number sets which element to access.

Word Offset

The Word Offset field is optional, and if used, defines which word of a multi-word element to access.

Bit Offset

The Bit Offset field is optional, and if used, defines which bit of the word to access.

Allen Bradley Plc Slot Numbering Software

Data Address Editor

The Data Address Editor provides a convenient tool to build Allen Bradley File Data Address strings.

To open the File Data Address Editor, click on the Browse button at the right side of the DataAddress field:

Variable Reference Format

The Variable Reference Format is used with CompactLogix and ControlLogix PLC Devices.

The Variable Reference Format is a string that defines the location of variable in a tag based Allen Bradley PLC. The format of the string is:

Variable[VarArrayIndexes].StructMember[ArrayIndex]

Where:

Variable is the name of the variable in the PLC.
VarArrayIndexes is an optional set of variable array indexes.
StructMember an optional structure member name.
ArrayIndex is an optional array index on the structure member.

Examples

Some examples of Allen Bradley File Data Addresses:

Address	Description
O:1, O0:1, O:1.0	The first word of output slot 1.
O:1/0, O0:1/0, O:1.0/0	The first bit of the first word of output slot 1.
I:5.1, I1:5.1	The second word of input slot 5
N:20, N7:20	Word 20 of the default integer file
N:20/15, N7:20/15	Bit 15 of word 20 of the default integer file
N10:15	Word 15 of user defined integer file 10

Allen Bradley Plc Slot Numbering Tool

Some examples of Allen Bradley Variable References:

Address	Description
FlowTemperature	A reference to a variable called FlowTemperature.
SCADAData.Pressure	A reference to Pressure member of the variable SCADAData.

Where Used

The Allen Bradley PLC Data Address Format is used in these contexts:

In the IOItemName field of an I/O Analog Data Point Tag when the tag is associated with an Allen Bradley PLC.
In the IOItemName field of a I/O Digital Data Point Tag when the tag is associated with an Allen Bradley PLC.
In the IOItemName field of a I/O Double Word Data Point Tag when the tag is associated with an Allen Bradley PLC.
In the IOItemName field of a I/O String Data Point Tag when the tag is associated with an Allen Bradley PLC.
In the IOItemName field of a I/O Word Data Point Tag when the tag is associated with an Allen Bradley PLC.
In the DataAddress field of an Allen Bradley Register Block.
In the DataAddress parameter of the DirectWriteBit Tag Command when used with an Allen Bradley PLC.
In the DataAddress parameter of the DirectWriteWord Tag Command when used with an Allen Bradley PLC.

Further Information

To learn about Allen Bradley Register Block Tags.

For an overview of the Allen Bradley Driver.

For the meaning of terms used in Fernhill SCADA.

There are a number of addressing schemes used by PLC manufacturers. Let’s take a quick look at how memory locations (including hardware I/O) are accessed with RSLogix 500. Along the way, let’s define some terms.

INSTRUCTION – RSLogix’s command language is comprised of “instructions”. An XIC (it looks like a normally open contact –] [– ) is an instruction. A timer is an instruction. A few of the most common instructions are described below.

BIT – an address within the PLC. It can be an input, output or internal coil, among others.

In RSLogix, there are a couple of ways to show the address of a bit. The default is:

[type]:[word]/[bit]

For example, an address that references an output of a MicroLogix 1100 is O:0/0. That is:

O:0/5 means that it is a physical output.
O:0/5 means that it uses Slot 0 (in the case of the 1100, this output is onboard)
O:0/5 means that it is the fifth output on the PLC.

By the way, don’t get the capital “O” confused with a zero.

RUNG – A section of the PLC ladder program that terminates in an output function of some type. Just like in an electrical ladder diagram, a rung has some type of output that is turned on or turned off by the preceding entities in the rung. The first rung in a ladder program is always 0000.

HARDWIRED INPUT – a physical connection to the PLC from an input device (switch or sensor, etc.).

Allen-Bradley uses the capital letter “I” to designate a hardwired input. An address that describes an input on an SLC 500 is I:4/0.

Similar to the output structure,

I:4/0 means that it is a physical input.
I:4/0 means that it uses Slot 4 (the 5th slot in the rack).
I:4/0 means that it is the first input on the card.

Don’t get the capital “I’s” confused with ones.

HARDWIRED OUTPUT – a physical connection from the PLC to an output device (relay or pilot light, etc.) As was said above, an address that references an output of an SLC 500 is O:5/0.

INTERNAL COIL
This is a programmable bit used to simulate a relay within the PLC. The internal coil has no connection to the outside world. It does not connect to an output card. Internal coils are used to store information. The “contacts” of this “relay” can then be used multiple times in other parts of the program.

In RSLogix, the “B3” (binary) file is commonly used for all the internal coils. There are many other words in other files that have bits you can use as internal coils, but we are going to stick with the B3 file for our application.

B3:0/0 means that it references an internal Binary file
B3:0/0 means that it uses the first word in the table
B3:0/0 means that it is the first bit in the word.

Note that, unlike the Output and Input files, you have to use the file number in the address. In this case, the default file number is 3.

TIMER
A timer is a programmable instruction that lets you turn on or turn off bits after a preset time.

The two primary types of timers are TON for “timer on delay” and TOF for “timer off delay”.

Timers in A-B SLC and MicroLogix processors use file 4 for their timers.

T4:0 means that it references an internal Timer file
T4:0 means that it uses the first timer in the table

The address T4:0 simply refers to the timer. Each timer has bits that turn on after the timing function is complete. You can address this bit by simply putting a “/DN” after the timer address. DN stands for “done”.

For example, if timer T4:0 is a TON (timer on delay), then the bit T4:0/DN will turn on after the timer has reached its preset value.

COUNTER
A counter is a programmable instruction that lets you turn on or turn off bits after a preset count has been reached.

Allen Bradley Plc Slot Numbering Chart

There are different types of counters available in the RSLogix, but the CTU (counter up) instruction covers everything we will talk about here.

Counters in A-B SLC and MicroLogix processors use file 5.

C5:0 means that it references an internal Counter file
C5:0 means that it uses the first counter in the table

The address C5:0 simply refers to the counter. Each counter has bits that turn on after the counting function is complete. You can address this bit by simply putting a “/DN” after the counter address. DN stands for “done”.

For example, if counter C5:0 is a CTU (counter up), then the bit C5:0/DN will turn on after the counter has reached its preset value.

–] [– Normally Open Contact
When used with a hardwired input, this instruction is off until there is a voltage applied to the input. The bit address then goes high, or on, and the instruction becomes “true.” It works the same way when it has the same address as an internal coil, except that the coil must be turned on by logic in the program.

Allen-Bradley calls these normally open contacts “XIC”, or “eXamine If Closed” instruction.

An XIC instruction can reference a hardwired input, a hardwired output, an internal coil or a timer done bit, among others.

–]/[– Normally Closed Contact
This is an inverted normally open contact.

When used with a hardwired input, this instruction is “true” until there is a voltage applied to the input. It then goes low, or off, and becomes “false.”

Allen Bradley Plc Port Number

It also can be used with an internal coil, becoming true when the coil is off and becoming false when the coil is on.

Allen-Bradley calls these normally closed contacts “XIO”, or “eXamine If Open” instructions.

-( )- Output Coil
When used with a hardwired output, this function is off until the logic in the program allows it to turn on. It then becomes “true”, and will energize the device that is wired to the respective output.

If it is used as an internal coil, it will toggle the instructions associated with it. That is, it will close a normally open instruction and open a normally closed instruction.

Allen-Bradley calls these outputs “OTE”, or “OutpuT Energize”.

An OTE may be used with a hardwired output or an internal coil.

Allen Bradley Plc Slot Numbering Machine

TRUE – A state that indicates an instruction is allowing logic to “flow” through it.

Also, if the logic in a rung turns on the output of the rung, then the rung is said to be true.

FALSE – Without stating the obvious, this is the opposite of true.

Excerpted from PLC Programming with RSLogix 500

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