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

Chapter 3

Programming

4. Enter values for operands 1 and 2.

You can enter these values from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand 1 - 102746 and operand 2 ­256384 produces the result 359130 when the addition function executes.
Figure 3.4 shows how the result is stored.

Figure 3.4

Addition Function Format After Execution

AF4

Operand 1

Operand 2

Result

Bit No

171615141312111076543210

S

(0)

S

(0)

S

(0) (0) (1) (0)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow)

DERE

1

02

467

562

843

593

301

Data Address
Word 201

Word 202

Word 203

Word 204

Result Address
Word 305

Word 306

11483

Entry and Display of Input and Result Values

Figure 3.5 shows one method for inserting input values and displaying input
values and results of AF4 addition computations. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests an AF4 addition. The second rung shows the two operands in its top
branch and the resultant sum in its lower branch.

313

Chapter 3

Programming

Figure 3.5

Addition Function Input and Result Display Rungs

AF4

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

01
201
305

201

202

203

204

G

G

G

G

102

746

256

384

305

306

G

G

359

130

Error Message

If the resultant sum has more than six integers, the error bit (bit 14) is set
indicating overflow.

AF4

Subtraction Function

An AF4 subtraction 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.

How to Enter an AF4 Subtraction Function

Storage

Bit

314

To program an AF4 subtraction 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.

2. Enter 02, the function number for AF4 subtraction.

This entry identifies that the function entered is to perform an AF4 subtraction
and that the processor use the data table format shown in Figure 3.6 when
executed. Operands 1 and 2 represent the two 6-digit numbers whose difference
you want to find. The six digits of operand 1 are represented in BCD by the
group 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 3.6

AF4 Subtraction Function Word Digit Format

General

Chapter 3

Programming

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

11484

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 3.7. The data address
eventually contains three digits of operand 2. 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.

315

Chapter 3

Programming

Figure 3.7

Subtraction Function Format After Address Entry

AF4

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

11485

316

4. Enter values for operands 1 and 2.

You can enter these values form the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand 1 = 102746 and operand 2
256384 produces the result -153638 when the subtraction function executes.
Figure 3.8 shows how the result is stored.

Operand 1

Bit No

Chapter 3

Programming

Figure 3.8

Subtraction Function Format After Execution

AF4

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

(0)

S

1

02

467

Data Address

201

202

Operand 2

Result

S

(0)

DERE

S

(0) (0) (1) (0)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow)

562

843

531

386

203

204

Result Address

305

306

11486

Entry and Display of Input and Result Values

Figure 3.9 shows one method of inserting input values and displaying input
values and results of AF4 subtraction computations. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests an AF4 subtraction. The second rung shows the two operands in its top
branch and the resultant difference in its lower branch.

Figure 3.9
Af4

Subtraction Function Input and Result Display Rungs

201

202

203

204

G

G

G

G

102

746

256

384

305

306

G

G

153

638

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

02
201
305

Storage

Bit

317

Chapter 3

Programming

Error Message

If the result has more than six integers, the error bit (bit 14) is set indicating
overflow.

AF4

Multiplication Function

An AF4 multiplication function operates on two 6-digit BCD numbers and
presents the results in a 12-digit BCD number.

(+

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

How to Enter an AF4 Multiplication Function

To program an AF4 multiplication 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.

2. Enter 03, the function number for AF4 multiplication.

This entry identifies that the function entered is to perform an AF4
multiplication and that the processor use the data table format shown in
Figure 3.10 when executed. Operands 1 and 2 represent two 6-digit numbers
whose product you want to find. The six digits of operand 1 are represented in
BCD by groups of bits labeled digit 1 through 6. Digit 1 and 6 are the most
significant and least significant digits respectively. Operand 2 and the 12 digits
of the result are labeled similarly.

318

Figure 3.10

AF4 Multiplication Function Word and Digit Format

General

Chapter 3

Programming

Bit No.

Operand 1

Operand 2

Result

171615141312111076543210

S

S

S

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

DE

Digit 1
(MSD)

Digit 7

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5Digit 4

Digit 8 Digit 9

Digit 6
(LSD)

Digit 6
(LSD)

Digit 6

Data Address

m

m + 1

m + 2

m + 3

Result Address

n

n + 1

n + 2

Digit 10

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

Digit 11

Digit 12

(LSD)

n + 3

11487

3. Enter a data address and a result address.

If we enter a data address of 201 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.11. The data address
eventually contains the most significant three digits of operand 1. The AF4
reserves the next three higher addresses for the least significant three digits of
operand 1 and the six digits of operand 2. The result address contains the most
significant three digits of the result. The AF4 reserves the next three higher
addresses for the remaining nine digits of the result.

319

Chapter 3

Programming

Figure 3.11

Multiplication Function format After Address Entry

AF4

Bit No.

Operand 1

Operand 2

Result

171615141312111076543210

S

S

S

DE

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 7

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5Digit 4

Digit 8 Digit 9

Digit 6
(LSD)

Digit 6
(LSD)

Digit 6

Data Address
201

202

203

204

Result Address
305

306

307

Digit 10

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

Digit 11

Digit 12

(LSD)

310

11488

320

Chapter 3

Programming

4. Enter values for operands 1 and 2.

You can enter these values from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand 1 - 000400 and operand 2 ­000200 produces the result 00000080000 (Figure 3.12).

Figure 3.12
AF4

Multiplication Function Format After Execution

Bit No.

Operand 1

Operand 2

Result

171615141312111076 54 3 2 1 0

S

(0)

S

(0)

S

(0)(0)(1)

DE

0

00

004

000

002

000

000

800

000

Data Address
201

202

203

204

Result Address
305

306

307

310

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)

11489

Entry and Display of Input and Result Values

Figure 3.13 shows one method you can use to enter values for operands 1 and 2
and for displaying the results of an AF4 multiplication. Although there are
several techniques for accomplishing this, we chose get instructions. The first
rung requests an AF4 multiplication. The top branch of the second rung shows
the two 6-digit operands while the lower branch shows the 12 digit product.

321

Chapter 3

Programming

Figure 3.13

Multiplication Function Input and Result Display Rungs

Af4

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

03
201
305

201

202

203

204

G

G

G

G

000

400

000

200

305

306

306

306

G

G

G

G

153

638

638

638

AF4 Division Function

An AF4 division function operates on two 6-digit BCD numbers and presents
the results in a 12-digit BCD number.

(+

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

How to Enter an AF4 Division Function

To program an AF4 division 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.

Storage

Bit

322

2. Enter 04, the function number for AF4 division.

This entry identifies that the function entered is to perform an AF4 division and
that the processor use the data table format shown in Figure 3.14 when
executed. Operands 1 and 2 represent two 6-digit numbers whose quotient you
wish to find. The six digits of operand 1 are represented in BCD by groups of
bits labeled digit 1 through 6. Digit 1 and 6 are the most significant and least
significant digits respectively. Operand 2 and the 12 digits of the result are
labeled similarly.

Figure 3.14

AF4 Division Function W

General

Chapter 3

Programming

ord and Digit Format

Bit No.

Operand 1

Operand 2

Result

17161514131211107 6 5 4 3 2 1 0

ER

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 7

Digit 10

S

S

DE

S

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5Digit 4

Digit 8 Digit 9

Digit 11

Digit 6
(LSD)

Digit 6
(LSD)

Digit 6

Digit 12

(LSD)

Data Address

m

m + 1

m + 2

m + 3

Result Address

n

n + 1

n + 2

n + 3

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Illegal Operand (Divide by Zero)
MSD = Most Significant Digit
LSD = Least Significant Digit

11490

3. Enter a data address and a result address.

If we enter a data address of 201 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.15. The data address
eventually contains the most significant three digits of operand 1. The AF4
reserves the next three higher addresses for the least significant three digits of
operand 1 and the six digits of operand 2. The result address contains the most
significant three digits of the result. The AF4 reserves the next three higher
addresses for the remaining nine digits of the result.

323

Chapter 3

Programming

Figure 3.15

Division Function Format After Address Entry

AF4

Bit No.

Operand 1

Operand 2

Result

171615141312111076543210

ER

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 4

Digit 1
(MSD)

Digit 7

Digit 10

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5

Digit 2 Digit 3

Digit 5Digit 4

Digit 8 Digit 9

Digit 11

Digit 6
(LSD)

Digit 6
(LSD)

Digit 6

Digit 12

(LSD)

S

S

S

DE

Data Address
201

202

203

204

Result Address
305

306

307

310

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Illegal Operand (Divide by Zero)
MSD = Most Significant Digit
LSD = Least Significant Digit

11491

324

Chapter 3

Programming

4. Enter values for operands 1 and 2.

You can enter these numbers from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand 1 = 000400 and operand 2

- 000200 produces the result 000002.000000 (Figure 3.16).

Figure 3.16
AF4

Division Function Format After Execution

Bit No.

Operand 1

Operand 2

Result

171615141312111076 54 3 2 1 0

S

(0)

S

(0)

DE

S

(0)(0)(1)ER(0)

0

00

004

000

002

000

020

000

000

Data Address
201

202

203

204

Result Address
305

306

307

310

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Illegal Operand (Divide by Zero)

11492

Entry and Display of Input and Result Values

Figure 3.17 shows one method you can use to enter values for operands 1 and 2
and for displaying the results of an AF4 division. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests an AF4 division function. The top branch of the second rung shows
the two 6-digit operands while the lower branch shows the 12 digit quotient.

325

Chapter 3

Programming

Figure 3.17

Division Function Input and Result Display Rungs

AF4

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

04
201
305

201

202

203

204

G

G

G

G

000

400

000

200

305

306

306

306

G

G

G

G

000

002

000

000

Error Message

If you divide by zero, the error bit (bit 14) is set and the result reads zero.

AF4 BCD to Binary Conversion Function

The AF4 BCD (binary coded decimal) to binary conversion function converts a
BCD number (from 0 to 4095) into a 12-bit binary number.

How to Enter an AF4 BCD to Binary Conversion Function

To program an AF4 BCD to binary conversion function, perform the following
steps:

Storage

Bit

326

1. Press [SHIFT][EAF] or [SHIFT][SCT] on the industrial terminal

keyboard. Figure 3.1 appears on the CRT.

Chapter 3

Programming

2. Enter 13, the function number for AF4 BCD to binary conversion.

This entry identifies that the function entered is to perform an AF4 BCD to
binary conversion and that the processor use the data table format shown in
Figure 3.18 when executed.

Figure 3.18
General

AF4 BCD to Binary Conversion Function Word and Digit Format

Bit No.

Operand

Result

171615141312111076543210

DE

Digit 1 (MSD)

(Always = 0)

Digit 4

ER

S

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = BCD Number > 4095 Entered)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 2

(Always = 0)

Digit 5

Digit 3

(Must be 3 4)

Digit 6
(LSD)

Data Address

m

m + 1

Result Address

n

11493

3. Enter a data address and a result address.

If we choose a data address of 200 and a result address of 300, the data table
format is as shown in Figure 3.19. The most significant three digits of the
operand (the BCD number we want to convert to binary) reside in the data
address word 200 and the least significant three digits reside in the next higher
address, 201. The first two digits are always zero and the third digit must not
exceed four. The number, converted to binary format, is stored in bits 0 through
13 in the result address, word 300.

Figure 3.19
AF4

BCD to Binary Conversion Function Format After Address Only

Bit No.

Operand

Result

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

Digit 2

(Always = 0)

Digit 5

(Must be

DE

Digit 1 (MSD)

(Always = 0)

Digit 4

ER

S

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = BCD Number > 4095 Entered)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 3

Digit 6
(LSD)

3 4)

Data Address
200

201

Result Address
300

11494

327

Chapter 3

Programming

Bit No.

Operand

4. Enter the operand.

You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. If we choose to enter 4095, the largest BCD
number that we can convert to a 12 bit binary number, we obtain the data table
configuration shown in Figure 3.20.

Figure 3.20
Af4

BCD to Binary Conversion Function Format After Execution

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

Data Address
200

(0)

S

004

201

Result Address
300

11495

Result

095

S

ER

DE

(0) (0) (1) (0)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = BCD Number > 4095 Entered)

111111111111

Entry and Display of Input and Result Values

Figure 3.21 shows one method for inserting input values and displaying inputs
and results of an AF4 BCD to binary conversion. Although there are other
methods for accomplishing this, we chose get instructions. The first rung
requests an AF4 BCD to binary conversion. The top branch of the second rung
shows the BCD number we want to convert (004095) in words 200 and 201.
The bottom branch shows in the hexadecimal notation FFF (bits 0 through 13 in
word 300 have the states shown in Figure 3.20).

Figure 3.21
AF4

BCD to Binary Conversion Function Input and Display Rungs

Execute Aux

Function

200

004

300

FFF

Function Number:
Data Addr:
Result Addr:

201

G

G

G

095

13
200
300

Storage

Bit

328

Chapter 3

Programming

Error Message

If you enter a BCD number larger than 4095, the error bit (bit 14) is set and the
result reads zero.

AF4 Binary to BCD Conversion Function

The AF4 binary to BCD conversion function converts a 12-bit binary number to
a BCD number (from 0 to 4095).

How to Enter an AF4 Binary to BCD Conversion Function

To program an AF4 binary to BCD conversion 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.

Bit No.

Operand

2. Enter 14, the function number for the AF4 binary to BCD conversion.

This entry identifies that the function entered is to perform an AF4 binary to
BCD conversion and that the processor use the data table format shown in
Figure 3.22 when executed.

Figure 3.22
General

AF4 Binary to BCD Conversion Function Word and Digit Format

171615141312111076543210

S

Digit 1 (MSD)

DE

S

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

(Always = 0)

Digit 4

12 Bit Binary Number

Digit 2

(Always = 0)

Digit 5

Digit 3

Digit 6
(LSD)

Data Address

m

Result AddressResult

n

n + 1

11496

3. Enter a data address and a result address.
If we choose a data address of 200 and a result address of 300, the data table

format is as shown in Figure 3.23. Bits 0 through 13 or word 200 are reserved
for the operand (the 12-bit binary number we want to convert to BDD). The
result address, 300, contains the most significant three digits of the resulting
BCD number and the least significant three digits reside in the next higher
address, 301. The first two digits of the BCD number are always zero and the
third digit can not exceed four.

329

Chapter 3

Programming

Figure 3.23

Binary to BCD Conversion Function Format After Address Entry

AF4

Bit No.

Operand

171615141312111076543210

Data Address

S

Digit 1 (MSD)

DE

S

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

(Always = 0)

Digit 4

12 Bit Binary Number

(Always = 0)

Digit 2

Digit 5

Digit 3

Digit 6
(LSD)

200

Result AddressResult
300

301

11497

4. Enter the operand.

You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. If we choose to set bits 0 through 13 in word
200, that is, insert the largest possible binary number in 12 bits, we obtain 4095
for the corresponding BCD number (Figure 3.24). The ones in bits 0 through
13 of word 200 indicate that each bit is set.

330

Bit No.

Operand

Result

Figure 3.24
AF4

Binary to BCD Conversion Function Format After Execution

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

S

S

(0) (0) (1)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)

11 11 11 11 11 11

DE

004

095

Data Address
200

Result Address
300

301

11498

Chapter 3

Programming

Entry and Display of Input and Result Values

Figure 3.25 shows one method for inserting input values and displaying inputs
and results of an AF4 binary to BCD conversion function. Although there are
other methods for accomplishing this, we chose get instructions. The first rung
requests an AF4 binary to BCD conversion function. The top branch of the
second rung shows the binary number (in the hexadecimal notation FFF) that
we want converted to BCD. In this example, the binary number is the largest
possible, with bits 0 through 13 of word 200 set as shown in figure 3.24. The
lower branch shows the resulting BCD number, 004095, in words 300 and 301.

Figure 3.25
AF4 Binary to BCD Conversion Function Input and Result Display Rungs

Execute Aux

Function

200

G

004
300

FFF

Function Number:
Data Addr:
Result Addr:

201

G

G

095

14
200
300

Storage

Bit

Sign Bits

If you encounter any binary data where the sign bit is not in bit 16, you must
move the sign bit into bit 16 of an auxiliary data table word prior to doing a
binary to BCD conversion. If, for example, the sign bit of your module is bit 15
in word 200, the rungs in Figure 3.26 permit you to make a binary to BCD
conversion. The first rung puts word 200 data into word 201. Rung two sets bit
16 in word 201 if bit 15 in word 200 is set. The AF4 binary to BCD conversion
function in rung three then uses word 201 as its data address.

331

Chapter 3

Programming

Figure 3.26
Transfer

200

G

200

15

of Sign Bit

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

14

201

AF4 Log to Base 10 Function

The AF4 log to the base 10 function finds the log of a 3-digit BCD integer. The
result is a 6-digit BCD number with an implied decimal point after the most
significant digit.

201

PUT

201

PUT

16

log (xxx.) - x.xx xxx

How to Enter an AF4 Log to Base 10 Function

To program an AF4 log to base 10 function perform the following steps:

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

terminal. Figure 3.1 appears in the CRT.

2. Enter 30, the function number for an AF4 log to base 10 function.

This entry identifies that the function entered is to perform an AF4 log to base
10 calculation and that the processor use the data table format shown in
Figure 3.27 when executed. The three digits of the number whose log you want
are represented in BCD by the digits labeled 1 through 3 in the operand. The
6-digit result is represented by digits labeled 1 through 6. The most significant
digit (MSD) and least significant digit (LSD) are labeled.

332

Figure 3.27

AF4 Log to Base 10 Function W

General

Chapter 3

Programming

ord and Digit Format

Bit No.

Operand

Result

171615141312111076543210

Digit 1
(MSD)

ER

Digit 1
(MSD)

Digit 4

DE

E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)

ER = Error Bit (1 = Input is 0)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6
(LSD)

Data Address

m

Result Address

n

n + 1

11499

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 3.28. The data address is
reserved for the three digits of the number whose log you want. The result
address, 305, is reserved for the first three digits of the resultant log; the next
higher address, 306, is reserved for the last three digits. The implied decimal
point in the result is after the MSD.

Bit No.

Operand

Result

Figure 3.28
AF4

Log to Base 10 Function Format After Address Entry

171615141312111076543210

Digit 1
(MSD)

DE

ER

E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)

ER = Error Bit (1 = Input is 0)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1

(MSD)

Digit 4

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6

(LSD)

Data Address
201

Result Address
305

306

11500

333

Chapter 3

Programming

Operand

4. Enter the operand.

You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand - 648 produces the result

2.81157 when the log function executes. Figure 3.29 shows how the result is
stored.

Figure 3.29
AF4 Log to Base 10 Function Format After Execution

171615141312111076543210Bit No.

648

Data Address
201

Result Address
305

306

Result

ER

(0) (1)

E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)

ER = Error Bit (1 = Input is 0)

DE

(0)

281

157

Entry and Display of Input and Result Values

Figure 3.30 shows one method for inserting the operand and displaying the
input value and result of an AF4 log to base 10 function. Although there are
several techniques for accomplishing this, we chose get instructions. The first
rung requests an AF4 log to base 10 function. The second rung shows the
operand 648 in word 201 in the upper branch and the desired log 2.81157 in
words 305 and 306 in the lower branch.

Figure 3.30
AF4 Log to Base 10 Function Input and Result Display Rungs

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

201
305

11507

30

334

201

G

648

305

G

281

Storage

Bit

306

G

157

Chapter 3

Programming

Error Messages

If you try to find the log of zero, the error bit is set and the result is zero.

AF4 Natural Log Functions

The AF4 natural log function finds the natural log of a 3-digit BCD integer to
the base e. The result is a 6-digit BCD value with an implied decimal point after
the most significant digit.

In (xxx.) - x.xx xxx

How to Enter an AF4 Natural Log Function

To program an AF4 natural log 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.

Bit No.

Operand

Result

2. Enter 31, the function number for the AF4 natural log function.

This entry identifies that the function entered is to perform an AF4 natural log
calculation and that the processor use the data table format shown in
Figure 3.31 when executed. The three digits of the operand (the number whose
natural log you want) and represented in BCD by the groups of bits labeled digit
1 through 3. The six digits of the result are labeled digit 1 through 6. A decimal
point is implied after the MSD.

Figure 3.31
General

AF4 Natural Log Function Word and Digit Format

171615141312111076543210

Digit 1
(MSD)

ER

Digit 1

(MSD)

Digit 4

DE

E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Input is 0)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6

(LSD)

Data Address

m

Result Address

n

n + 1

11501

3. Enter a data address and a result address.

335

Chapter 3

Programming

If we enter a data address of 201 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.32. The data address
eventually contains the operand. The result address (word 305) contains the first
three digits of the result and word 306 contains the last three digits.

Figure 3.32
AF4 Natural Log Function Format After Address Entry

Bit No.

Operand

Result

171615141312111076543210

Digit 1
(MSD)

ER

Digit 1

(MSD)

Digit 4

DE

E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Input is 0)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6
(LSD)

Data Address
201

Result Address
305

306

11502

4. Enter the number for the operand.

You can enter this number from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand = 648 produces the result

6.47389 when the natural log function executes. Figure 3.33 shows how the
result is stored.

336

Operand

Result

Figure 3.33
AF4

Natural Log Function Format After Execution

171615141312111076543210Bit No.

64 8

DE

(0) (1) (0)

ER

E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)
ER = Illegal Operand (1 = Input is 0)

64 7

38 9

Data Address
201

Result Address
305

306

11503

Chapter 3

Programming

Entry and Display of Input and Result Values

Figure 3.34 shows one method for inserting the operand and displaying the
input value and result of an AF4 natural log function. Although there are
several techniques for accomplishing this, we chose get instructions. The first
rung requests an AF4 natural log function. The second rung shows the operand
648 in word 201 in the upper branch and the desired natural log 6.47389 in
words 305 and 306 in the lower branch.

Figure 3.34
AF4 Natural Log Function Input and Result Display Rungs

Execute Aux

Function

Function Number:
Data Addr:
Result Addr:

31
201
305

201

G

648

305

G

647

306

G

389

Storage

Error Messages

If you try to find the natural log of zero, the error bit is set and the result is zero.

AF4 Exponential Function

The AF4 exponential function finds the value of the exponential function ex.
The result is in terms of a base number r and a power of 10, s, by which the base
number is multiplied to obtain the exponential function value. The equation is:

+x

e

=r(10)

s

where:
x= +

X.XX

r = resultant base number = X.XX

Bit

s = the exponent of 10 = +

X.

How to Enter an AF4 Exponential Function

To program an AF4 exponential 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.

337

Chapter 3

Programming

2. Enter 32, the function number for an AF4 exponential function.
This entry identifies that the function entered is to perform an AF4 exponential

calculation and that the processor use the data table format shown in
Figure 3.35 when executed.

Figure 3.35
General AF4 Exponential Function W

ord and Digit Format

Bit No.

Operand

Result Base r

s (Power of 10)

171615141312111076543210

S

DE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)

D = Done Bit (1 = Function Complete)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 1

(MSD)

Digit 1 (MSD) Digit 3
(Always = 0) (Always = 0)

Digit 2

Digit 2

Digit 2

Digit 3
(LSD)

Digit 3
(LSD)

(LSD)

Data Address

m

Result Address

n

n + 1

11504

3. Enter a data address and a result address.
If we choose a data address of 200 and a result address of 305, the AF4

establishes the data table format shown in Figure 3.36. The three digits of the
word 200 are reserved for the operand (the power to which e is being raised).
The result address is reserved for the three digits of 4, the base number of the
answer with an implied decimal after the MSD. The next higher address, word
306, is reserved for s, the power of 10. The implied decimal point of exponent s
is after the LSD; the MSD and digit 2 are always zero. The base number r is
accurate to +

.01.

338

Figure 3.36
AF4 Exponential Function Format After Address Entry

Bit No.

Operand

s (Power of 10)

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

S

DE

S

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

Digit 1
(MSD)

Digit 1

(MSD)

Digit 1 (MSD) Digit 3
(Always = 0) (Always = 0)

Digit 2

Digit 2

Digit 2

Digit 3
(LSD)

Digit 3
(LSD)

(LSD)

Data Address
200

Result AddressResult Base r
305

306

11505

Operand

Chapter 3

Programming

4. Enter the operand.

You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of an operand (exponent) of e) of 9.42
yields an exponential function value of 1.23(10)
305 and the exponent of ten resides in word 306 as shown in Figure 3.37.

Figure 3.37
AF4 Exponential Function Format After Execution

171615141312111076543210Bit No.

S

(0)

942

004

. The base r resides in word

Data Address
200

s (Power of 10)

(0) (1)

DE

S

(0)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)

123

004

Result AddressResult Base r
305

306

11506

Entry and Display of Input and Result Values

Figure 3.38 shows one method for inserting input values and displaying input
values and results of an AF4 exponential function. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests execution of an AF4 exponential function. The second rung contains

9.42, the exponent of e in word 200 with an implied decimal point after the first
digit. It also shows the result, (1.23)(10)

004

, in the form of 123 in word 305 and

004 in word 206. The decimal points are implied.

Figure 3.38
AF4

Exponential Function Input and Result Display Rungs

201

G

648

305

G

647

306

G

389

Execute Aux

Function

Function Number:
Data Addr:
Result Addr: 305

32

Storage

Bit

339

Chapter 3

Programming

AF4 Power Function

The AF4 power function evaluates y+

x and gives the result in terms of a base
number r and a power of 10, s, by which you multiply this base number to
obtain the power function value. The equation is:

y+

x = r(10)

+s

where:

y = input base = XXX.

x = input exponent = XX.X

r = result base = X.XX

s = resultant exponent = +

XX. (The first digit is always zero)

A request for zero to the zero power will result in plus one.

How to Enter an AF4 Power Function

To program an AF4 power 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.

2. Enter 33, the function number for an AF4 power function.

This entry identifies that the function entered is to perform an AF4 power
function calculation and that the processor use the data table format shown in
Figure 3.39 when executed. The data address is reserved for the three digits of
the base number y. Digits 1 and 3 are the most significant digit (MSD) and least
significant digit (LSD) respectively. The implied decimal point is after the
LSD. The three digits in the next higher address are reserved for the exponent,
x, with an implied decimal point after digit 2. The three digits of the result
address are reserved for the result base, r, with the decimal point after the MSD.
The next higher address is reserved for the resultant exponent s. Digit one of
the exponent s is always zero; the implied decimal point is after digit 3.

340

Figure 3.39
General

Bit No.

Base y

Chapter 3

Programming

AF4 Power Function W

171615141312111076543210

S

ord and Digit Format

Digit 1
(MSD)

Digit 2

Digit 3
(LSD)

Data Address

m

Exponent x

Result Base, r

s (Power of 10)

3. Enter a data address and a result address.
If we enter a data address of 200 and a result address of 300, the AF4

establishes the data table format shown in Figure 3.40. Word 200 is reserved
for the base y and word 201 is reserved for the exponent x. The result address,
word 300, is reserved for the result base r; word 301 contains the resultant
exponent s.

Figure 3.40
AF4 Power Function Format After Address Entry

S

DE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)

D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow when y > 9.99(10) )
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 1

ER

(MSD)

Digit 1 (MSD) Digit 3
(Always = 0)

Digit 2

Digit 2

Digit 2

x 099.

Digit 3
(LSD)

Digit 3
(LSD)

(LSD)

m + 1

Result Address

n

n + 1

11508

Bit No.

Base y

Exponent x

Result Base, r

s (Power of 10)

171615141312111076543210

S

S

DE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow when y > 9.99(10) )
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

ER

Digit 1

(MSD)

Digit 1 (MSD) Digit 3
(Always = 0)

Digit 2

Digit 1
(MSD)

Digit 2

Digit 2

x 099.

Digit 3
(LSD)

Digit 2
(LSD)

Digit 3
(LSD)

(LSD)

Data Address
200

201

Result Address
300

301

11509

341

Chapter 3

Programming

4. You can enter base y and exponent x values from the keyboard of the

industrial terminal or through ladder diagram functions. Entry of y - 124
in word 200 and 2 - 02.0 in word 201 produces the result 15376 when the
power function executes. Figure 3.41 shows how the result is stored as

1.53(10)

Figure 3.41
AF4 Power Function Format After Execution

171615141312111076543210Bit No.

Base y

4

. The result is truncated.

S

(0)

124

Data Address
200

Exponent x

Result Base, r

s (Power of 10)

S

(0)

DE

(0) (1) (0)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)

D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow when y > 9.99(10) )

ER

S

(0)

020

153

004

x 099.

201

Result Address
300

301

11510

342

Chapter 3

Programming

Entry and Display of Input and Result Values

Figure 3.42 shows one method for inserting the input values and displaying
input values and result of an AF4 power function. Although there are several
techniques for accomplishing this, we chose get instructions.

The first rung requests the AF4 to evaluate a power function. The top branch of
the second rung contains the input base, 124, in word 200 and the input
exponent 02.0 in word 201. The lower branch of rung 2 contains the result,

1.53(10
in word 301. The implied decimal points in the result base and result exponent
are after digits 1 and 3 respectively.

Figure 3.42
AF4

4

) in the form of result base (153) in word 300 and result exponent (004)

Power Function Input and Result Rungs

Execute Aux

Function

200

G

124

300

G

153

Function Number:
Data Addr:
Result Addr: 300

201

G

020

301

G

004

33

200

Error Message

If you input a negative number for the input base y, the absolute value of y is
used and the error bit is set.

If yx >

9.99(10)

099

, the error bit is set, and a result of zero is returned.

AF4 Reciprocal Function

Storage

Bit

The AF4 reciprocal function finds the value of the reciprocal of a 6-digit BCD
number and presents the result in a 6-digit BCD number.

1
+

xxx xxx.

If you try to find the reciprocal of +

= +.xxx xxx

1, the result will read .999 999 with the

appropriate sign.

343

Chapter 3

Programming

How to Enter an AF4 Reciprocal Function

To program an AF4 reciprocal 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.

2. Enter 34, the function number for an AF4 reciprocal function.

This entry identifies that the function entered is to perform an AF4 reciprocal
calculation and that the processor use the data table format shown in
Figure 3.43 when executed.

Figure 3.43
General AF4 Reciprocal Function W

ord and Digit Format

Bit No.

Operand

Result

171615141312111076543210

S

DE

SER

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (Illegal Operand, 1 = Input is 0)

MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 4 Digit 5

Digit 1

(MSD)

Digit 4

Digit 2

Digit 2

Digit 5

Digit 3

Digit 6
(LSD)

Digit 3

Digit 6

(LSD)

Data Address

m

m + 1

Result Address

n

n + 1

11511

344

Chapter 3

Programming

3. Enter a data address and a result address.

If we choose a data address of 200 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.44. The data address
eventually contains the most significant three digits of the operand (the number
whose reciprocal we seek). The next higher address, word 201, is reserved for
the three least significant digits of the operand. The result address contains the
most significant three digits of the result; the next address word 306, contains
the least significant three digits of the result. The implied decimal points in the
operand and the result are after the LSD and before the MSD respectively.

Figure 3.44
AF4

Reciprocal Function Format After Address Entry

Bit No.

Operand

Result

171615141312111076543210

S

DE

SER

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (Illegal Operand, 1 = Input is 0)

MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 4 Digit 5

Digit 1

(MSD)

Digit 4

Digit 2

Digit 2

Digit 5

Digit 3

Digit 6
(LSD)

Digit 3

Digit 6
(LSD)

Data Address
200

201

Result Address
305

306

11512

4. Enter the operand.

You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand 124 yields as its reciprocal
the value .008064 as shown in Figure 3.45.

345

Chapter 3

Programming

Operand

Figure 3.45

Reciprocal Function Format After Execution

AF4

171615141312111076543210Bit No.

S

(0)

00 0

12 4

Data Address

Result

200

G

000

305

008

DE

SER

(0) (0) (0) (0)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)

D = Done Bit (1 = Function Complete)
ER = Error Bit (Illegal Operand, 1 = Input is 0)

00 8

06 4

Result Address

Entry and Display of Input and Result Values

Figure 3.45 shows one method of inserting input values and displaying input
values and results of an AF4 reciprocal function. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests execution of an AF4 reciprocal function. The top branch of the second
rung shows the 6-digit operand while the lower branch shows the 6-digit result.

Figure 3.46
AF4

Reciprocal Function Input and Result Display Rungs

Execute Aux

Function

Function Number:
Data Addr:
Result Addr: 305

201

G

124

306

G

G

064

34

200

11513

Storage

Bit

346

Error Message

If you try to find the reciprocal of zero, the error bit (bit 145) is set and the
result reads zero.

Chapter 3

Programming

AF4 T

rigonometric Function Sin xxx.

The AF4 sine function finds the sine of a 3-digit BCD angle. The input angle is
in degrees. The AF4 presents the result as a 6-digit value with an implied
decimal point after the most significant digit.

Bit No.

Operand

sin xxx. = +

x.xx xxx

How to Enter an AF4 Sine Function

To program an AF4 sine 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.

2. Enter 35, the function number for the AF4 sine function.

This entry identifies that the function entered is to perform an AF4 sine
calculation and that the processor use the data table format shown in
Figure 3.47 when executed. The three BCD digits in the operand labeled digit 1
through 3 represent the angle with an implied decimal point after digit 3. The
6-digits in the result are the sine of the angle with an implied decimal point after
digit 1.

Figure 3.47
General

AF4 Sine Function W

171615141312111076543210

S

Digit 1
(MSD)

ord and Digit Format

Digit 2

Digit 3
(LSD)

Data Address

m

Result

S

DE

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

Digit 1

(MSD)

Digit 4

Digit 2

Digit 5

Digit 3

Digit 6

(LSD)

Result Address

n

n + 1

11514

3. Enter a data address and a result address.

If we enter a data address of 205 and a result address of 310, the AF4
establishes the data table format shown in Figure 3.48. The data address, word
205, is reserved for the three digits of the angle whose sine we want. The result

347

Chapter 3

Programming

address, word 310, is reserved for the most significant three digits of the sine;
the least significant three digits are stored in the next higher address, word 311.

348

Figure 3.48

Sine Function Format After Address Entry

AF4

Chapter 3

Programming

Bit No.

Operand

Result

171615141312111076543210

S

DE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)

D = Done Bit (1 = Function Complete)
MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 1

(MSD)

Digit 4

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6

(LSD)

Data Address
205

Result Address
310

311

11515

4. Enter an angle value in degrees (operand).

You can enter the angle from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of 080 for the angle produces the result
sine 080

0

= 0.98480 (Figure 3.49).

Operand

Result

Figure 3.49
AF4

Sine Function Format After Execution

171615141312111076543210Bit No.

S

(0)

DE

S

(0) (0) (1)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)

080

098

480

Data Address
205

Result Address
310

311

11516

349

Chapter 3

Programming

Entry and Display of Input and Result Values

Figure 3.50 shows one method for inserting the input angle and displaying the
input and the result of an AF4 sine function. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests the AF4 sine function. The top branch of the second rung shows the
angle value 080o in word 205. The lower branch shows the resultant sine 080
= 0.98480 in words 310 and 311 with an implied decimal point after the first
digit.

Figure 3.50
AF4

Sine Function Input and Result Display Rungs

Execute Aux

Function

205

G

080

310

G

098

Function Number:
Data Addr:
Result Addr: 310

311

G

480

35

205

0

Storage

Bit

350

AF4 Trigonometric Function, Cos xxx.

The AF4 cosine function finds the cosine of a 3-digit BCD angle. The input
angle is in degrees. The AF4 presents the result as a 6-digit value with an
implied decimal point after the most significant digit.

cos xxx. = +

X.XX XXX

How to Enter an AF4 Cosine Function

To program an AF4 cosine 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.

2. Enter 36, the function number for the AF4 cosine function.

This entry identifies that the function entered is to perform an AF4 cosine
calculation and that the processor use the data table format shown in
Figure 3.51 when executed. The three BCD digits in the operand labeled digit 1
through 3 represent the angle with an implied decimal point after the third digit.
The 6-digits in the result are the cosine of the angle with an implied decimal
point after the first digit.

Figure 3.51

AF4 Cosine Function Word and Digit Format

General

Chapter 3

Programming

Bit No.

Operand

Result

171615141312111076543210

S

DE

S

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

Digit 1
(MSD)

Digit 1

(MSD)

Digit 4

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6

(LSD)

Data Address

m

Result Address

n

n + 1

11517

3. Enter a data address and a result address.

If we enter a data address of 205 and a result address of 310, the AF4
establishes the data table format shown in Figure 3.52. The data address, word
205, is reserved for the three digits of the angle whose cosine we want. The
result address, word 310, is reserved for the most significant three digits of the
cosine; the least significant three digits are stored in the next higher address,
word 311.

Bit No.

Operand

Result

Figure 3.52
AF4

Cosine Function Format After Address Entry

171615141312111076543210

S

DE

S

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

Digit 1
(MSD)

Digit 1

(MSD)

Digit 4

Digit 2

Digit 2

Digit 5

Digit 3
(LSD)

Digit 3

Digit 6

(LSD)

Data Address
205

Result Address
310

311

11518

351

Chapter 3

Programming

Operand

4. Enter an angle value in degrees (operand).

You can enter the angle from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of 080 for the angle produces the
result cosine 080

Figure 3.53
AF4

Cosine Function Format After Execution

171615141312111076543210Bit No.

S

(0)

0

= 0.17364 as shown in Figure 3.53.

080

Data Address
205

Result

DE

S

(0) (0) (1)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)

D = Done Bit (1 = Function Complete)

017

364

Result Address
310

311

11519

Entry and Display of Input and Result Values

Figure 3.54 shows one method for inserting the input angle and displaying the
input and the result of an AF4 cosine function. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests the AF4 cosine function. The top branch of the second rung shows the
angle value 080

0

080

= 0.17364 in words 310 and 311 with an implied decimal point after the

0

in word 205. The lower branch shows the resultant cosine

first digit.

Figure 3.54
AF4

Cosine Function Input and Result Display Rungs

352

205

G

080

310

G

017

311

G

364

Execute Aux

Function

Function Number:
Data Addr:
Result Addr: 310

36

205

Storage

Bit

Chapter 3

Programming

AF4 Square Root Function

The AF4 square root function operates on a 3-digit BCD integer and gives the
result in terms of a base number 4 and a power of 10, s, by which the base
number is multiplied to obtain the resultant square root value. The equation is:

+X

1/2

= r(10)

s

where:

x = XXX.

r = resultant base number = X.XXX

s = the exponent of 10 = x

How to Enter an AF4 Square Root Function

To program an AF4 square root 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.

2. Enter 37, the function number for an AF4 square root function.

This entry identifies that the function entered is to perform an AF4 square root
calculation and that the processor use the data table format shown in
Figure 3.55 when executed.

Bit No.

Operand

Result Base r

s (Power of 10)

Figure 3.55
General

AF4 Square Root Function Word and Digit Format

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

S

DE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Negative Operand)

MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 1

ER

(MSD)

Digit 1 (MSD) Digit 3
(Always = 0)

(Always = 0)

Digit 2

Digit 2

Digit 2

Digit 3
(LSD)

Digit 3
(LSD)

(LSD)

Data Address

m

Result Address

n

n + 1

11520

353

Chapter 3

Programming

3. Enter a data address and a result address.
If we choose a data address of 200 and a result address of 305, the data table is

as shown in Figure 3.56. The three digits of word 200 are reserved for the
operand (the number whose square root we want). The result address (word

305) is reserved for the three digits of 4, the base number of the answer with an
implied decimal point located after the MSD. The next higher address than the
result address, (word 306) contains s, the power of 10. The implied decimal
point in this number is after the LSD; the MSD and digit 2 are always zero.

Figure 3.56
AF4

Square Root Function Format After Address Entry

Bit No.

Operand

Result Base r

s (Power of 10)

Operand

17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0

S

DE

S

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Negative Operand)

MSD = Most Significant Digit
LSD = Least Significant Digit

Digit 1
(MSD)

Digit 1

ER

(MSD)

Digit 1 (MSD) Digit 3
(Always = 0)

Digit 2

Digit 2

Digit 2

(Always = 0)

Digit 3
(LSD)

Digit 3
(LSD)

(LSD)

Data Address
200

Result Address
305

306

11521

4. Enter the operand.
You can enter the operand from the keyboard of your industrial terminal or

through ladder diagram functions. Entry of operand 144 produces the number
12 when the square root function is completed. Figure 3.57 shows how the
operand and results are stored.

Figure 3.57
AF4 Square Root Function Format After Execution

171615141312111076543210Bit No.

Data Address
200

(0)

S

144

354

Result Base r

s (Power of 10)

DE

(0)

ER

S

(0) (1)

E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Negative Operand)

120

001

Result Address
305

306

11522

Chapter 3

Programming

Entry and Display of Input and Result Values

Figure 3.58 shows one method for inserting input values and displaying input
values and the results of AF4 square root computations. Although there are
several techniques for accomplishing this, we chose get instructions.

The first rung requests the AF4 square root function. The second rung displays
in word 200 the number 144, whose square root is desired. It also shows the
resulting square root (12) in the form of 1.20 in word 305 and in word 306 it
shows the power of 10,001, by which 1.2 must be multiplied to obtain
(1.2)(10)

Figure 3.58
AF4

200

G

144

305

G

120

001

= 12.

Square Root Function Input and Result Display Rungs

Function Number:
Data Addr:
Result Addr: 305

306

G

001

Execute Aux

Function

37

200

Storage

Bit

Error Message

If you try to find the square root of a negative number, the error bit is set and
the absolute value of the input number is used.

355

Index

A

Accuracy, 39

Addition, 39

Address

Data, 32, 312
Invalid, 33
Result, 32, 312
Valid, 33

AF4 (PROM), 11

Applications, 12

Automatic checks, 33

B

BCD to binary, 326

Binary to BCD, 329

Bits

Done, 39
Enable, 39
Error, 39
Sign, 39, 331
Unused, 39

Execution time, 34

Exponential function, 337

F

Function number, 31, 32

function sequence, 32

Functions, 12

H

Handling precautions, 21

Humidity, 21

I

Ilegal opcode, 31

Illegal address, 33

Installation, 21, 22

Interlock system, 34

Invalid address, 33

C

Checks, 31, 33

Data address, 32, 312
Result address, 32, 312
Scan time, 34

Contamination, 21

Cosine function, 350

D

Data address, 32, 312

Data table (valid areas), 32

Data table format, 37, 311

Digit location, 38, 312

Division, 322

Done bit, 39

E

Enable bit, 39

Error bit, 39

Error messages, 38

L

Log to base 10, 332

Log to base e, 335

M

Memory backup, 23

Multiplication, 318

N

Natural log, 335

P

Power function, 340

Programming, 31

PROM, 11

R

Recriprocal function, 343

I–2

Index

Result, 32, 313

Result address, 32, 312

S

Sign bit, 39

Sine function, 347

Square root, 353

Static electricity, 21

Status bits, 39

T

Time, Execution, 34

U

Ultraviolet light, 11, 21

Unused bits, 39

W

Word arrangement, 37

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Publication

Supersedes

17726.5.3 - March 1984

Publication 1772-828 - March 1984

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