Rockwell Automation 1772-AF4, D17726.5.3 User Manual

Auxiliary Function PROM
(Cat. No. 1772AF4)
for the Mini-PLC-2/15 Controller

User Manual

Table of Contents

Introduction 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Functions 12
Applications 12
Manual's Purpose 12
Audience 12

Installation 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installation/Removal Handling Instructions 21
Installation 22
Removal 24

Programming 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AF4 Function Sequence 32
AF4 Automatic Checks 33
Programming

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Specific Mathematical Functions

37. . . . . . . . . . . . . . .

Introduction

Chapter

1

General

Installation of the Auxiliary Function (AF) PROM (cat. no. 1772-AF4 in your
Mini-PLC-2/15 controller lets you expand its mathematical capabilities.

For simplification, throughout this manual we refer to the Auxiliary Function
PROM (cat. no. 1772-AF4) as the AF4.

The AF4 can only be used with the series A Mini-PLC-2/15 processor module,
firmware revision 11 or later (cat. no. 1772-LV). The AF4 can only be used
with the series B Mini-PLC-2/15 processor module, firmware revision 4 or later.
Programming the AF4 functions with either series Mini-PLC-2/15 processor
module requires the Industrial Terminal (cat. no. 1770-T3).

The AF4 has a 2K (16 bit) word section to which you can transfer your program
(for backup memory) and a 2K word section for higher mathematical functions.
You can only transfer your program into the AF4 with the series B PLC-2/15
controller (Table 1.A). Series A Mini-PLC-2/16 Processor EPROM (publication
1770-91) describes program transfer to PROM. With the series A PLC-2/15
controller, program transfer to the AF4 is not possible.

Table 1.A
AF4

PROM Response Controller

MiniPLC2/15 Controller

[1]

2K section for higher mathematical functions would also be erased and all AF1 function
capabilities lost. Once erased, the AF4 functions are irretrievable.

NOTE: The AF4 is sensitive to ultraviolet (UV) light, therefore when exposed
to UV light, both the program and the auxiliary functions are erased. The AF4’s
transparent window is covered with the product label to avoid accidental
alteration of memory from ultraviolet light sources. Do not remove this label.

Series

Read Write Erase [1]

AYesNo No

BYesYes No

You can erase the 2K memory backup portion of the AF4 with ultraviolet light. However, the

User Program 2K Words

11

Chapter 1

Introduction

Functions

Applications

The AF4 performs the following arithmetic functions:

Six digit add and subtract
Six digit multiply and divide
BCD to binary conversion
Binary to BCD conversion
Logarithm of a three digit number to the base 10
Logarithm of a three digit number to the base 3
Exponential function -e
Power function -y

+X

+X

Reciprocal of a number - 1

+X
Sine of an angle - sin X
Cosine of an angle - cos X
Square root of a number -x

0.5

These arithmetic functions have applications in various industries such as food
processing, machine tool work, and material handling. Applications in these
industries could be weighing, blending, batch processing, scaling, positioning,
test stands, and heat treating. The square root function is frequently used for
flow measurement and in mining applications.

Manual's Purpose

Audience

This manual shows you how to install and program the AF4 in your
Mini-PLC-2/15 controller.

We assume that you are familiar with programming and operation of the
Mini-PLC- 2/15 and the Industrial Terminal (cat. no. 10770-T3). If this is not
the case, refer to the appropriate publications or see our Publication Index
(publication SD499).

WARNING: : Use only Allen-Bradley authorized programming
devices to program Allen-Bradley programmable controllers.
Using unauthorized programming devices may result in
unexpected operation, possibly causing equipment damage
and/or injury to personnel.

12

Installation

Chapter

2

General

Installation/Removal Handling Instructions

During AF4 installation, take special care not to bend or contaminate the pins.
Bent or dirty pins can prevent proper AF4 programming and use. The AF4’s
transparent window is covered with the product label to avoid accidental
alteration of memory from UV light sources. Do not remove this label. Store
the AF4 in its shipping container when not installed in a Mini-PLC-2/15
processor.

The AF4 can be damaged during routine handling if proper precautions are not
taken to reduce static electricity discharges.

Recommended precautions include:

Handle the AF4 by the case without touching its pins.

Use a static free work station.

Wear a conductive wrist strap which has a minimum 200k ohms resistance

and is connected to earth ground.

Ground tools prior to contacting the AF4.

Connect static-free work station to ground through a minimum 200k ohm

resistance.

Control the relative humidity of the installation area - ideal conditions are

40% to 60% relative humidity.

The following is a list of things that should not be done:

Do not handle styrofoam, plastic, or cellophane-covered articles such as

combs, cigarette packages, and candy immediately prior to handling an AF4.
Do not hand the AF4 to someone who is not antistatic protected.

Do not install the AF4 in areas which might contaminate or foul the pins of

the AF4 device.
Do not handle the AF4 by its pins.
Do not slide the AF4 across any surface.
Do not place the AF4 in a non-conductive plastic bag.

21

Chapter 2

Installation

When these precautions are followed, the potential difference between the AF4
pins is reduced thereby reducing the problems associated with static discharges.

Installation

The AF4 fits into a 28-pin ZIF (zero insertion force) socket, which is located
under a hinged door at the lower side of the Mini-PLC-2/15 processor
(Figure 2.1).

Figure 2.1
PROM

Socket

10715I

On the underside of the PROM door is a label that illustrates PROM
installation. The notch on the AF4 PROM, when installed, must correspond to
the notch shown on the label. Figure 2.2 shows a properly installed AF4.

22

Figure 2.2
AF4

Installed

PROM
Notch

Lock

OFF

PROM Installation

1772AF4

DO NOT

UP

ERASE

ON

Release

11590

Chapter 2

To access the PROM socket, remove the Mini-PLC-2/15 processor module from
the I/O chassis. If you desire to maintain processor memory contents, connect
an external battery pack (Figure 2.3) to the processor with the Mini-Processor
Transport Cable (cat. no. 1772-CD) prior to removing the module from the
chassis.

Figure 2.3
External

Battery Backup

Battery Pack

(Cat. No. 1771BB)

MiniPLC2/15 Processor

(Cat. No. 1772LV)

MiniProcessor
Transport Cable

(Cat. No. 1772CD)

11182

To install the AF4, perform the following steps (Figure 2.2):

1. Turn the mode select switch to PROG.

2. Remove AC power from the I/O chassis power supply.

3. Remove the processor module from the I/O chassis.

4. Check all AF4 pins to ensure they are not bent or dirty.

5. Loosen the screw and lift the PROM door.

6. Push the ON tab in to unlock the socket.

7. Position the AF4 as shown in Figure 2.2. Be sure the notch on your AF4

faces the OFF tab.

8. Line up the AF4 as shown in Figure 2.2 and seat in the socket. Be sure the

pins are aligned as they bend easily.

9. Lock the AF4 in place by pushing the OFF tab in.

10.Close the PROM door and tighten the screw.

23

Chapter 2

Installation

Removal

To remove the AF4, perform the following steps:

1. Turn the mode select switch to PROG.

2. To maintain processor memory contents connect an external battery pack

to the processor with the mini-processor transport cable (Figure 2.3).

3. Remove AC power from the I/O chassis power supply.

4. Remove the processor module from the I/O chassis.

5. Loosen the screw, lift up the PROM door, and push the ON tab in to

unlock the socket (Figure 2.2).

6. Carefully remove the AF4 and store it in its shipping container.

24

Programming

Chapter

3

General

You access the AF4 by pressing [SHIFT][EAF] (execute auxiliary function) or
[SHIFT][SCT] on the keyboard of your Industrial Terminal (cat. no. 1770-T3).
The instruction is an output instruction and may be preceded on a rung by
condition instructions. Once you enter the function, the block diagram of
Figure 3.1 appears on the CRT. To program a specific mathematics functions,
you would enter the appropriate function number (Table 3.A). If you enter a
non-existent function number, the following occurs:

When the processor attempts to execute a function number which does not exist
on the AF4, the response of the processor depends upon whether the keyswitch
is in the RUN or RUN/PROGRAM position.

The responses are:

In the RUN position, the processor stops running and the CRT displays
PROCESSOR FAULT and CHANGE PROCESSOR TO PROGRAM MODE.
The processor and memory LEDs illuminate. After you change processor
operation to program mode the LEDs turn off and the CRT displays MODE
SELECTION menu and PLC-2 RUN TIME ERROR, PRESS 11 TO
CONTINUE. When you press 11 the CRT displays and intensifies the rung
containing the illegal opcode and states ILLEGAL OPCODE INTENSIFIED
INSTRUCTION LINKED WITH CAUSE OF ERROR.

In the RUN/PROGRAM position, the processor stops running and the CRT
displays MODE SELECTION menu and PLC-2 RUN TIME ERROR, PRESS
11 TO CONTINUE. When you press 11 the CRT displays and intensifies the
rung containing the illegal opcode and states ILLEGAL OPCODE
INTENSIFIED INSTRUCTION LINKED WITH CAUSE OF ERROR.

31

Chapter 3

Programming

Table 3.A
Function

Numbers for the AF4

Function

Number

01 Add

02 Subtract

03 Multiply

04 Divide

13 BCD to Binary conversion

14 Binary to BCD conversion

30 Log to base 10

31 Natural log (log to base e)

32 Exponential

33 Power

34 Reciprocal

35 Sine

36 Cosine

37 Square Root

Mathematical Operation

You enter an existent function number and then enter data and result addresses
(we will explain this in detail later). The processor then places a number in the
data address.

AF4 Function Sequence

32

When the Mini-PLC-2/15 controller encounters an AF4 function during
program execution and the rung is true, the processor performs the following
steps:

1. Saves its present position in the user program.

2. The interlock system grants access to the AF4 function.

3. Reads the operand’s data stored in the data address that you entered.

4. Reads the result address which you entered.

5. Determines the location of the mathematical routine requested by the

function number.

6. Executes the routine in the AF4 area. (See Avoiding Excessive AF4

Execution Times.)

7. Writes the results at the result address in the data table.

8. Returns program execution to the next instruction in the user program after

the AF4 function is completed. (See Avoiding Excessive AF4 Execution
Times.)

9. Readies itself for the next AF4 operation.

Chapter 3

Programming

AF4 Automatic Checks

To guard against improper program execution, automatic check routines are
incorporated in the AF4. The processor uses these routines to prevent the
following:

Executing AF4 functions having invalid function addresses
Spending so much time executing AF4 functions that the controller neglects

its main program and I/O scans

Invalid

Function Addresses

Valid AF4 function addresses include the I/O image table and the data table
(except word 027). Specifically, valid addresses are from 010 to 026, from 030
to 077, and from 110 to the end of the data table. Result addresses must not
reside in the input image table.

When a user programmed function has an invalid address, the response of the
processor depends upon whether the keyswitch is in the RUN or
RUN/PROGRAM position.

The response are:

In the RUN position, the processor stops running and the CRT displays
PROCESSOR FAULT and CHANGE PROCESSOR TO PROGRAM MODE.
The processor and memory LEDs illuminate. After you change processor
operation to program mode the LEDs turn off and the CRT displays MODE
SELECTION menu and PLC-2 RUN TIME ERROR, PRESS 11 TO
CONTINUE. When you press 11 the CRT displays and intensifies the rung
containing the illegal address and states ILLEGAL ADDRESS INTENSIFIED
INSTRUCTION LINKED WITH CAUSE OF ERROR.

In the RUN/PROGRAM position, the processor stops running and the CRT
displays MODE SELECTION menu and PLC-2 RUN TIME ERROR, PRESS
11 TO CONTINUE. When you press 11 the CRT displays and intensifies the
rung containing the illegal address and states ILLEGAL ADDRESS
INTENSIFIED INSTRUCTION LINKED WITH CAUSE OF ERROR.

33

Chapter 3

Programming

A

voiding Excessive AF4 Execution T

Table 3.B lists execution times for AF4 functions. To avoid excessive AF4
function execution times, an interlock system is designed into the AF4. This
system automatically checks and does the following:

Permits no AF4 function to run longer than 6ms without returning processor

scan to the processor.

During a program scan each true AF4 function rung which can be completed

in a single scan will be completed as it is encountered. However, upon

encountering a true AF4 function rung which requires multiple program

scans to complete, all other true AF4 function rungs will be “locked out”

until sufficient program scans complete the active AF4 function rung.

Once started, it completes an AF4 function prior to starting the next AF4

function encountered in the user program which has a true rung condition.

imes

Limits the number of enabled AF4 functions in a program to 50. You may

include more functions but you must ensure that no more than 50 are enabled

at one time. This requirement only applies where you have programmed a

function that requires more than one scan to complete.

This time listed in Table 3.B includes:

Overhead for AF4 interlock system

One run through the portion of the AF4 specified by the particular function

To obtain the time required from activation of the input that makes the rung
containing the AF4 function true until the correct answer for the function is in
the data table, you must add the following times to the values in Table 3.B:

Input delay time (from specification for specific input)

One program scan time and one I/O scan time multiplies by the number of

scans specified in Table 3.B

Methods for determining these times are presented in Mini-PLC-2/15, Series B,
Programmable Controller Programming and Operations Manual (publication
1772- 804).

34

Chapter 3

Programming

Table 3.B

Execution T

AF4

Log

Natural log

Function

imes

[1]

Reciprocal

Exponential

Powers

35

Chapter 3

Programming

Sine

Function

N
A

W

u
v

o

m
g

r

b
.

s

e
T

t

r
i

T

o
m

i

f
e

m

S
e

c
a
n
s

Cosine

Square Root

00.5

(y

)

BCD to Binary

Binary to BCD

36

Function

Addition

Chapter 3

Programming

N
A

W

u
v

o

m
g

r

b
.

s

e
T

t

r
i

T

o
m

i

f
e

m

S
e

c
a
n
s

Subtraction

Multiplication

Division

[1]

These times are calculated for a single AF4 function. Overhead for AF4 lock

maintenance and multiple runs through the ladder program to complete some function is

included.

Programming Specific Mathematical Functions

In this section we explain the following for each of the AF4 functions:

What it is
How to enter it in your program
Its format in the data table

a. word arrangement

37

Chapter 3

Programming

b. digit location

Sample entry and display rungs. Although there are several techniques to

enter this data, we use get instructions.

Error messages. If an AF4 function has special error message responses to

specific illegal programming procedures, we state these responses.

38

Chapter 3

Programming

Status Bits

The most significant four bits of the most significant word of the result data
area are reserved for status bits. These bits have the following meanings:

Enable - bit 17
Sign - bit 16
Done - bit 15
Error bit - bit 14

The enable bit is set at the start of an AF4 function and reset upon completion.

The sign bit, if set, indicates a negative value.

The done bit is reset at the start of an AF4 function and set upon completion.

The error bit is a general error flag that indicates overflow and invalid operand
or result errors. Individual functions determine the actual state of this bit.

Throughout this manual, unused status bits are shown blank for the following
reasons:

Whether the content of an unused status bit is an input word is 0 or 1 is

irrelevant as such bits are ignored in AF4 function execution.

The AF4 reset unused status bits in result words. For simplicity these bits are

left blank.

Accuracy

In the series A, revision A AF4, the typical error is +

1 in the least significant
digit (LSD). However, two functions have errors which exceed this limit.
Function 32, e

+x

, has error limits of +8 and -1 in the least significant digit for a

range of x from 0.00 to -9.99.

Function 33, y

+x

, has error limits of +6 and -1 in the least significant digit when

x is negative.

AF4 Addition Function

An AF4 addition function operates on two 6-digit BCD numbers and presents
the result in a third 6-digit BCD number.

(+

xxx xxx.) + (+xxx xxx.) = +xxx xxx.

39

Chapter 3

Programming

How to enter an AF4 Addition Function

To program an AF4 addition function, perform the following steps:

1. Press [SHIFT][EAF] or [SHIFT][SCT] on the keyboard of your industrial

terminal. Figure 3.1 appears on the CRT

Figure 3.1
Execute

Numbers shown are default values and must be replaced
by your values. The number of default address digits
originally displayed, 3 or 4, depends on the size of the
data table.

Auxiliary Function Format

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

01
010
010

310

Chapter 3

Programming

2. Enter 01, the function number for AF4 addition.

This entry identifies that the function entered is to perform an AF4 addition and
that the processor use the data table format shown in Figure 3.2 when executed.
Operands 1 and 2 represent the two 6-digit numbers we wish to add. The six
digits of operand 1 are represented in BCD by the groups of bits labeled digit 1
through 6. Digit 1 and digit 6 are the most significant and the least significant
digits respectively. This digit labeling system also applies to operand 2 and the
result.

Figure 3.2
General

AF4 Addition Function Word and Digit Format

Operand 1

Operand 2

Result

Bit No.

171615141312111076543210

S

S

DERE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 6
(LSD)

Digit 6
(LSD)

Digit 6
(LSD)

Data Address

m

m + 1

m + 2

m + 3

Result Address

n

n + 1

11481

311

Chapter 3

Programming

3. Enter a data address and a result address.

If we select a data address of 201 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.3. Be careful not to select
data and result addresses so close together that the addresses of the operands
following the data address overlap your result address. The data address
eventually contains three digits of operand 1. The AF4 reserves the next three
higher addresses for digits 4 through 6 of operand 1 and digits 1 through 6 of
operand 2. The result address contains the most significant three digits of the
result and the next higher address contains the least significant three digits.

Figure 3.3
AF4

Addition Function Formal After Address Entry

Operand 1

Operand 2

Result

Bit No.

171615141312111076543210

S

S

DERE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 6
(LSD)

Digit 6
(LSD)

Digit 6
(LSD)

Data Address
201

202

203

204

Result Address
305

306

11482

312