Rockwell Automation 1772-LV, D17726.6.1 User Manual

Bulletin 1772 Mini-PLC-2/15 Programmable Controller

Assembly and Installation Manual

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

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

Definition Fundamental Concepts 11 PreAssembly

& Installation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Controller Components 21. . . . . . . . . . . . . . . . . . . . . . . . . . .

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

System Power Supply 23 I/O Chassis 27 MiniPLC2/15 Processor 28 Input/Output Modules 211 Industrial Terminal 214 UserSupplied

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Equipment

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11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

214. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Assembly and Installation 31. . . . . . . . . . . . . . . . . . . . . . . . .

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

System

Installation Recommendations General Grounding Information 38 Chassis PreAssembly 311 I/O Chassis and Power Supply Mounting 317 I/O Chassis Assembly 318 Wiring/Cabling Incoming AC Wiring Guidelines 333 Industrial T

Installation

erminal Installation

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

325. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

337. . . . . . . . . . . . . . . . . . . . . . . . . . .

System Start-Up 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Start-Up 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Checkout Before Applying Power 41 Checkout With Power Applied To Selected Devices 42 Checkout

of Machine Motion

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47. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maintenance and Troubleshooting 51. . . . . . . . . . . . . . . . . . .

General 51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preventive Maintenance 51 Spare Parts 51 Troubleshooting 51 System Power Supply 52 Mini-PLC-2/15 Processor 511 1771

I/O Modules

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514. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contentsii

Specifications 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mini-PLC-2/15 Processor 61 System Power Supply 62 I/O

Equipment

Industrial Terminal 63

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63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction

Chapter

General

PC Definition

Fundamental Concepts

The Bulletin 1772 Mini-PLC-2/15 Programmable Controller is a digital, electronic, solid state industrial programmable controller capable of monitoring and controlling up to 128 I/O devices. The Controller has a Processor, a power supply and a number of user-selected I/O Modules chosen for the number and type of I/O devices in the user’s application. By selecting the appropriate modules, the user can assemble a complete programmable controller system to meet the application requirements.

The Processor and the selected I/O Modules are housed in a single I/O Chassis, which can be mounted inside an enclosure with a working depth of 8 inches.

A programmable controller (PC) is a solid state logic control device used for industries as diverse as petrochemical, food processing, pulp and paper, mining, steel and metals, and cement to name a few.

As the term “programmable” implies, PC memory can be readily changed to meet application needs.

The Controller continuously monitors the status of devices connected as inputs. Based on input device status and the User Program, the Controller controls the devices connected as outputs. These input and output devices may be of different types with various voltage and current ranges. They may include:

limit, float, selector, and pressure switches pushbutton switches thumbwheel switches alarms, indicators, and annunciator panels solenoids motors and motor starters transducers various solid state devices, including TTL and Analog instrumentation

11

Chapter 1

Introduction

The Processor stores all I/O device status data in a central read/write memory. This allows the latest status data to be accessible during the scanning of the user program. PC programming instructions allow the Processor to perform:

Timing/Counting operations Arithmetic (+, -, x, :) operations Data transfers and comparisons Program Jumps/subroutines Word/File transfers Sequencer operations Block transfer operations Data highway communication

The Mini-PLC-2/15 Programmable Controller uses readily understandable symbols in a ladder diagram format. The ladder diagram program is manually entered into memory using an Industrial Terminal. An Industrial terminal is also used to edit the program and monitor the status of the user’s I/O devices as well as interface the Mini-PLC-2/15 Processor with a peripheral device. Peripheral devices including keyboards/printers, the Digital Cassette Recorder (Cat. No. 1770-SA) and the Data Cartridge Recorder (Cat. No. 1770-SB) allow a variety of additional capabilities:

PreAssembly & Installation

loading/storing/verifying the program using magnetic tape generating a hard-copy printout of the ladder diagram program or total

memory

generating various types of reports in a user-programmed format

Indicators on the various Controller components are used to show I/O device, Processor, and power supply status. These indicators help to diagnose a fault situation quickly when troubleshooting the PC system.

Read this manual carefully before assembling or installing any component. It is strongly recommended that the hardware and installation personnel work closely with the Mini-PLC-2/15 programmer at start-up.

Certain aspects of the programmable controller may be new to many individuals. For this reason, Publication SG1-1.1, “Application Considerations for Solid State Controls” should be read, as it provides general background information on solid state controls.

WARNING: To avoid personal injury and equipment damage, completely read and thoroughly understand the contents of this Manual before attempting to assemble and install the Mini-PLC-2/15 Controller and/or any of its components.

12

Controller Components

Chapter

General

The Mini-PLC-2/15 Programmable Controller (Figure 2.1) is made up of the following major components:

System Power Supply(Cat. No. 1771-P1) I/O Chassis (Cat. No. 1771-A1, -A2 or -A4) Mini-PLC-2/15 Processor Module (Cat. No. 1772-LV) A number of Bulletin 1771 I/O Modules.

Each of these components and their associated cables must be specified by the user when ordering the Mini-PLC-2/15 Programmable Controller. This section will identify and describe the hardware associated with each of these Mini-PLC2/15 Controller components. This will enable the user to assemble and install the components as described in Chapter 3. For additional information, refer to the respective Product Data Sheet for the component.

21

Chapter 2

Controller Components

System Power Supply (Cat. No. 1771P1)

Battery Pack (Cat. No. 1771BB)

Figure 2.1 MiniPLC2/15

MiniPLC2/15 Processor (Cat. No. 1772LV)

32 I/O 64 I/O 128 I/O

Programmable ControllerComponents

I/O Chassis Assembly

(Cat. No. 1771A1, A2, A4)

22

I/O Power Cable (Cat. No. 1771CL or CM)

I/O Module

Field Wiring Arm

10104-I

Chapter 2

Controller Components

System Power Supply

The System Power Supply (Cat. No. 1771-P1) is the required power source for the Mini-PLC-2/15 Controller (Figure 2.1). It converts the incoming AC voltages into the proper DC voltages to power the Processor and I/O Modules.

The System Power Supply can operate on either 120V AC or 220/240V AC. It provides a regulated output of 5.1V DC to power the logic circuitry of the Processor and I/O Modules. It also provides 5V DC for the memory circuitry of the Processor module.

The 5.1V output provides a maximum current of 6.5 amperes for the Processor and I/O Modules. Thus, the current requirements of the selected I/O Modules and Processor Module added together cannot exceed 6.5 amperes. The current requirements for available modules are listed in Table 1.A.

The System Power Supply is protected against undervoltage, overvoltage and overcurrent conditions. it constantly monitors the incoming AC voltage for proper levels (98 to 132V AC for 120V AC operation; 196 to 250V AC for 220/240V AC operation). The power Supply allows some margin for variation from this normal voltage range. There is a minimum voltage of 92V for 120V AC operation and 184V for 220/240V AC operation. if the AC line voltage drops below the minimum voltage for more than one-half cycle, the Power Supply signals the Processor to stop communication with the I/O Modules before invalid I/O data is transmitted. Once the correct AC level returns, communication with the I/O Modules is re-established.

Figure 2.2 System

Power Supply

Battery Pack (Cat. No. 1771BB)

10694I

23

Chapter 2

Controller Components

Battery

The Battery Pack (Cat. No. 1771-BB) is shipped standard with the System Power Supply and consists of:

An optional lithium battery (Cat. No. 1770-XO) can be ordered for use with the Battery Pack, is preferred.

The Battery Pack provides a convenient form of RAM memory backup power to the Processor when power from the System Power Supply is interrupted. It provides this memory backup power when the Processor is seated in the left-most slot of the I/O chassis. An external Battery Pack can also maintain memory content when the Processor is removed from the I/O Chassis. This is done by connecting them together with the Mini-Processor Transport Cable (Cat. No. 1772-CD) as shown in Figure 2.3.

I/O Power Cable

An I/O Power Cable (Figure 2.1) is used to connect the System Power Supply and the Battery Pack to the I/O Chassis. To accommodate two Power Supply mounting configurations, this cable is available in two lengths:

Pack

A metal Battery Housing (Cat. No. 1771-BH) A mounting Hardware Set (Cat. No. 1771-BX) Two D-size alkaline batteries (Cat. No. 1771-BA)

Cat. No. 1771-CL I/O Power Cable (1 ft/30.5 cm) Cat. No. 1771-CM I/O Power Cable (5 ft/1.5 m)

24

Table 1.A Module Reference Chart

Chapter 2

Controller Components

Module's

Module Cat. No.

AC/DC (120V) Input DC (1224V) Input DC (48V) Input Isolated AC/DC (120V) Input Analog (8 bit) Input Analog (12 bit) Input

TTL Input DC (2428V) Input Encoder/Counter (5V)

Encoder/Counter (1224V) 1771IK 1.4A 68, 2022

AC/DC (220/240V) Input DC (530V) Selectable Input Fast Response DC (1224V) Input DC (1224V) Driver Logic Input Thermocouple Input

1771IA 1771IB 1771IC 1771ID 1771IE 1771IF

1771IG 1771IH 1771IJ

1771IM 1771IQ

1771IT 1771IV 1771IX

Load on

System

Power

Supply

74mA 74mA 74mA 50mA

400mA

1.3A

122mA

74mA

1.4A

75mA

150mS

74mA 74mA

2.0A

Keying Band

Positions

Between Nos.

46, 1012 46, 1416

46, 1618 46, 2830 46, 2630 68. 2224 46, 3234

46, 3436

46, 1618 68. 1820 46, 3234

46, 3234

68, 3032 68, 2426

68, 3234

810, 1214 810, 1820 810, 2022

Field

Wiring Arm

(Cat. No.

1771 )

WA WA WA WD WB WB WB

WC WA WB WB

WB WB

WA WC

WA WA

WE

Color Coded

Label

Red Blue Blue Red Pink Pink Pink

Pink

Blue Brown Brown

Brown Brown

Red

Blue

Pink

Thermocouple Input Expander AC (120V) Output DC (1224) Output DC (48V) Output Isolated AC (120V) Output Analog (12 bit) Output

TTL Output AC (220/240V) Output Contact Output Gray Encoder Input (8 bit) MiniPLC2/15 Processor Communication Adapter Communication Controller Communication Controller Data Highway Interface/Modem Modem Interface

1771IY 1771OA 1771OB 1771OC 1771OD 1771OF

1771OG 1771OM 1771OY 1771DL

1772LV 1771KA 1771KC 1771KD 1771KF 1771KG

Input Fuse

500mA 210mA 165mA 165mA 225mA

1.4A

168mA 225mA 420mA 120mA

2.0A

1.2A

1.0A

810, 2022

46, 1214 46, 1820 46, 2022 46, 3032

24, 68

46, 3234

68, 1012 68, 2830 68, 1618 46, 2426

4042, 5456

46, 2224 68, 1214

46, 2224

WE WA WA WA WD

WB

WC WA WD WB

Pink

Orange

Green Green

Orange

Yellow Yellow

Gray Orange Orange

Brown

A slow-blow fuse (Figure 2.2) is used to guard against overcurrent conditions on the AC input line. The Power Supply is shipped with a 1-amp fuse in the fuse holder for 120V operation. For 220/240V operation, a 0.5-amp fuse is required and is included with the Power Supply.

25

Chapter 2

Controller Components

Terminal Strip

AC input connections are made to the terminals on the Power Supply labeled L1 and L2. L1 is the high side of the AC line and L2 is the low side (Figure 2.2).

Power

Supply Indicators

The two indicators on the front of the System Power Supply (Figure 2.2) are:

DC ON BATTERY LOW

The red DC ON indicator illuminates when the System Power Supply is operating properly; that is, the AC line voltage and DC output voltages are within their normal ranges. If this indicator is OFF, the incoming AC voltage may be low, the AC line fuse may have blown, or the Power Supply may have overloaded or been shorted.

Figure 2.3 External

Battery Backup

MiniPLC2/15 Processor (Cat. No. 1772LV)

Battery Pack (Cat. No. 1771-BB)

MiniPLC2/15 Processor Transport Cable (Cat. No. 1772CD)

10105-I

In some “brownout” situations, it is possible that the DC ON indicator might be illuminated while the Processor is disabled. This is because the Power Supply can supply the output voltage to maintain Processor logic, even through the AC line voltage has dropped below the normal range.

26

The BATTERY LOW indicator flashes when the Battery Pack voltage is low, the batteries are not installed or they have been installed with incorrect polarity. At this level, the batteries can support Processor memory for approximately one week, however memory content should be checked and reentered if necessary.

Chapter 2

Controller Components

Optional Power Supply Source

It is permissible to use the 1771-P2 Auxiliary Power Supply in place of the 1771-P2 System Power Supply. It should be noted, however, that RAM memory will be lost if an AC power loss occurs. One of two cables is used with this power supply:

1771-CE Power Cable (1 ft/30.5 cm) 1771-CD Power Cable (5 ft/1.5 m)

I/O Chassis

The I/O Chassis is the compact, slotted until that houses the Mini-PLC-2/15 Processor Module and the I/O Modules. There are three I/O Chassis sizes available (Figure 2.4):

32 I/O Chassis (Cat. No. 1772-A2), containing 4 I/O Module slots 64 I/O Chassis (Cat. No. 1771-A2), containing 8 I/O Module slots 128 I/O Chassis (Cat. No. 1771-A4), containing 16 I/O Module slots

Each I/O Chassis is able to fit into a working enclosure eight inches deep.

I/O Chassis are designed to permit Controller expansion. If a 32 I/O or 64 I/O Chassis is used and more I/O points are needed, a larger Chassis can be installed without rewiring. User wiring is connected to Field Wiring Arms which can be removed from the smaller Chassis and snapped onto the corresponding positions of the larger Chassis. Also, when Field Wiring Arms and I/o modules are placed in corresponding slots on the larger Chassis, the originally programmed addresses of the user I/O device are still valid and need not be changed.

The backplane of the Chassis has sockets for each module, a socket for Power Supply connection and a Switch Group Assembly for determining output response to a fault. latches on top of the Chassis snap down to hold the modules securely in place and provide labeling for module identification.

Shipped standard with each I/O Chassis are a number of Field Wiring Arms (Cat. No. 1771-WA), one for each I/o Module slot. If special Field Wiring Arms are required, they are shipped with the I/O Module. In addition, a package of plastic Keying Bands (Cat. No. 1777-RK) is shipped with each I/O Chassis. The Keying Bands provide an easy method for the user to key an I/O Module slot to accept only one type of I/O Module. use of these keying bands is strongly recommended.

27

Chapter 2

Controller Components

MiniPLC2/15 Processor

Backplane Sockets

The Mini-PLC-2/15 Processor Module (Cat. No. 1772-LV) is the central processing unit and memory of the programmable controller. It has 2K words of memory for the Data Table, User Program and messages. it can monitor and control up to 128 I/O devices that are wired to I/O Modules in the I/O Chassis. The Processor examines data from input devices, processes this data according to the User Program, and transmits data to control the output devices. In addition, the Processor monitors the status of its own operation, of data in memory, and of power from the System Power Supply. Orderly shutdown is provided if a malfunction from any of these points is detected.

The Mini-PLC-2/15 Processor (Figure 2.5) has three diagnostic indicators, a Mode Select Switch, an INTERFACE port and an EPROM access door. In addition,the Processor has a memory write protect feature that is active when a programmed EPROM is in place in the Processor.

Figure 2.4 I/O

Chassis Sizes

28

Switch Group Assembly

Power Supply Socket

32 I/O 64 I/O 128 I/O

10106-I

Diagnostic

I ndicators

There are three diagnostic indicators on the front of the Processor to show the status of its operation (Figure 2.5). They are:

PROCESSOR - When the Mode Select Switch is in the TEST, RUN or

RUN/PROG position, this red indicator illuminates if a hardware fault in the Processor occurs or the Processor cannot scan the memory.

MEMORY - In the TEST, RUN or RUN/PROGRAM mode, this red

indicator illuminates if the Mini-PLC-2/15 Processor detects no user

Chapter 2

Controller Components

memory, a discrepancy in memory data, or a parity error. This indicator is normally OFF.

In the PROGRAM mode this red indicator is used during EPROM programming. While EPROM programming is in progress, this indicator will blink ON and OFF. When EPROM programming has been successfully completed without error, this indicator will stay OFF. If an error in EPROM programming occurs, this indicator will come ON and stay ON.

This indicator will also flash if EPROM transfer at power-up is bad.

RUN - This green indicator illuminates when the Mini-PLC-2/15 Processor

is operating with the Mode Select Switch in the RUN or RUN/PROG position and the outputs are enabled.

Figure 2.5 MiniPLC2/15

Processor

10695bI

29

Chapter 2

Controller Components

Mode

Select Switch

The Mode Select Switch (Figure 2.5) places the Processor in one of four operating modes:

PROG - This switch position places the Processor into the PROGRAM mode

of operation. The User Program instructions are entered into memory in this switch position. EPROMs are programmed in this mode. All output devices are disabled. When a programmed EPROM is already in place, this mode is limited by the Memory Write Protect feature. See section titled Memory Write Protect for details.

TEST - This switch position allows the User Program to be tested by

enabling inputs but not outputs. This allows debugging of the User Program.

RUN - This switch position allows the Processor to scan and execute the

User Program. Changes to the Data Table or User Program are not permitted in this switch position. Output devices will be energized according to the User Program.

RUN/PROG - This switch position allows the Processor to function as it does

in the RUN position. On-line changes to the Data Table or User Program are permitted in this switch position. When a programmed EPROM is already in place, this mode is limited by the Memory Write Protect feature. See section titled Interface Socket for details.

When the keyswitch is in the RUN/PROG position, the Processor can be placed in one of three remote modes from the 1770-T3 Industrial Terminal keyboard:

REMOTE RUN/PROGRAM - the default mode. When the keyswitch is

turned to the RUN/PROG position, the Processor automatically enters this mode. On-line changes to the program and Data Table are allowed in this mode. When a programmed EPROM is already in place, this mode is limited by the Memory Write Protect feature. See section titled Interface Socket for details.

REMOTE PROGRAM - identical to the PROGRAM mode. The program

scan and I/O scan will be halted. All outputs are disabled. Going into this mode from REMOTE RUN/PROGRAM will reset an I/O fault, and clear a memory parity error.

REMOTE TEST - identical to the TEST mode. The program scan will be

running, but all outputs are disabled. Going into this mode from REMOTE RUN/PROGRAM will reset an I/O fault as does physically changing the keyswitch position from RUN/PROG or RUN to TEST.

210

Chapter 2

Controller Components

INTERFACE

The 15-pin socket labeled INTERFACE is used in connecting the Processor to the Industrial Terminal (Cat. No. 1770-T3) for programming, report generation or monitoring. This socket is also used to connect an external Battery Pack to the Processor so the Processor can be removed from the I/o Chassis without loss of memory. When programming an EPROM this INTERFACE socket is used to connect the 25.5V Power Supply to the Processor.

EPROM

The EPROM Access Door on the side of the Processor covers a 28-pin EPROM socket, which is used to house an optional 24-pin EPROM memory chip (Erasable Programmable Read Only memory) (Cat. No. 1770-XP). The EPROM provides the user with a 2K word non-volatile memory backup system. Programmed EPROMs can be erased with an ultraviolet light as described in Publication 1770-915, EPROM Programming.

Memory

When a programmed EPROM is in place in the Processor, a Memory Write Protect feature becomes active. This means values from word address 2008 to the end of memory are protected and cannot be altered by programming.

Socket

Access Door

rite Protect

Input/Output Modules

The I/O Modules (Figure 2-6) contain the necessary circuitry to interface the user’s I/O devices to the Mini-PLC-2/15 Processor.

Each I/O circuit has optical isolation to guard against high-voltage transients that can damage the Mini-PLC-2/15 Controller’s logic circuitry. Optical isolation is rated at 1500V RMS.

Many Input Modules have filtering circuitry to suppress contact bounce and to guard against recognition of transients as data.

Most I/O modules have indicators that show the ON/OFF status of each input or output device connected to it. These indicators are useful during start-up, monitoring, and troubleshooting. Output modules with fuses also have an additional indicator that illuminates if an output fuse in the module has blown.

I/O modules are available for devices with different voltage levels and characteristics. A color-coded label on each I/O module identifies the general type of module and voltage range. Table 1.A lists the general information on each I/O Module and the Processor Module. The Product Data Sheets for the I/O Modules include a detailed description, Module specifications, connection diagrams and keying information.

211

Chapter 2

Controller Components

Figure 2.6

Input and Output Modules

Typical

(a) Output Module (b) Input Module

10841I

Field Wiring Arms

Wiring to and from user I/O devices connects to a separate Field Wiring Arm for each I/O module. The Field Wiring Arm is a terminal strip that pivots up and down for quick, easy insertion and removal of I/O modules (Figure 2.7) without disturbing filed wiring. This aids in start-up and troubleshooting by shortening the time needed to replace I/O modules, thus decreasing down-time.

Cat. No. 1771-WA Field Wiring Arms are shipped with the I/O Chassis (one for each I/O Module slot). This Field Wiring Arm is used with most I/O modules. if a certain module requires a different Field Wiring Arm, it is shipped with that module. In this case, use the Field Wiring Arm that comes with the module.

212

Chapter 2

Controller Components

I/O

Addressing

Each terminal on a Field Wiring Arm is identified by a 5-digit address (Figure 2.8). The 5 digits in the terminal address directly correspond to a memory location in the Processor’s Data Table and designate the following:

The first digit is either a 0 for outputs or a 1 for inputs.

The second digit refers to the Rack Number (always 1 for the Mini-PLC-2/15

System).

The third digit refers to the Module Group Number (0-7). A Module Group

consists of two adjacent I/O Module slots in the I/O Chassis starting at the left (Figure 2.9). The Module Group Numbers for each pair of I/O slots are identified on labels on the Chassis latches.

The fourth and fifth digits of the address refer to the Terminal number within

the Module Group (00-07, 10-17).

Figure 2.7 Field

iring Arms

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Chapter 2

Controller Components

Industrial Terminal

The Industrial Terminal System (Cat. No. 1770-T3) is used to enter, monitor, edit and troubleshoot the User Program in the memory of the Mini-PLC-2/15 Processor (Figure 2.10). In addition, it can be used for report generation or to interface peripheral devices to the Processor.

The 1770--T1 or -T2 Industrial Terminals can be used with the Mini-PLC-2/15 Processor, however, they will limit the capabilities of the Processor. When using the 1770-T1 or -T2 Industrial Terminal, the Mini-PLC-2/15 Processor will be limited in the following ways:

Up to 256 word Data Table Up to 104 Timers/ Counters I/O forcing in one Module Group at a time Mini-PLC-2 processor instruction set

Figure 2.8 Fivedigit

Address

01012

Output=0 Input = 1

Rack Number, Always 1 for Mini-PLC-2/15

Terminal Number (00-07, 10-17)

Module Group Number (0-7)

10107-I

UserSupplied Equipment

214

In addition to Mini-PLC-2/15 Controller components, the user can supply other equipment for Controller installation including:

An enclosure, for mounting the Controller and shielding it from noise and

airborne contaminants

Emergency-Stop switches, variable in type and number Master Control Relay, to enable and disable I/O power by manual control Disconnects, normally a part of any electrical installation

Isolation transformers or constant voltage transformers, as application needs

dictate User power supplies, for I/O devices not powered directly from the AC line Suppression devices, for noise-generating equipment, including inductive

loads in series with hard contacts

Figure 2.9

Groups

Module

01234567

0 1234567

32 I/O

Chapter 2

Controller Components

64 I/IO

128 I/O

Figure 2.10 Industrial Terminal (Cat. No. 1770T3)

10108-I

10296I

215

Chapter

Assembly and Installation

General

Safety is a primary consideration in programmable controller installations and operations. The procedures in this section consider the safety of the operator, of the controlled equipment and of the Controller. These procedures are intended to supplement the applicable codes and ordinances that govern wiring and installation practices. Personnel installing the Controller system should become familiar with local codes as well as these procedures.

A well-planned layout is essential for the installation of the Mini-PLC-2/15 Controller. Various considerations necessary for planning the installation are discussed in this section.

Once the layout is planned, the Controller components can be assembled and installed into a workable system. The sequence of events presented in this section is a suggested approach to facilitate the assembly and installation of the components.

CAUTION: To avoid equipment damage, thoroughly read and understand this entire Manual before installing or operating the Mini-PLC-2/15 Controller.

System Installation Recommendations

There are general recommendations to consider for layout of the Controller system. These recommendations are the result of both product testing and Allen- Bradley’s cumulative experience with solid state industrial controls. They provide useful guidelines for most Mini-PLC-2/15 Controller installations.

These recommendations are intended to make the Controller an integral part of the user’s manufacturing facility. Some of the installation recommendations for user-supplied equipment are general in nature. Environmental conditions, the individual application and local codes and ordinances dictate the specific types of layout and wiring of user-supplied installation equipment.

Environmental

Special care should be taken in industrial environments that may contain one or more conditions adverse to solid state controls. The user’s plant may include equipment which produces heat or electrical noise. Line voltage variations may also occur in some locations.

Considerations

31

Chapter 3

Assembly and Installation

EXCESSIVE HEAT

For most applications, normal convection cooling keeps Controller components within the 0

to 600C ambient operating range. Thus, the proper spacing of

components within the enclosure is usually sufficient for heat dissipation.

There are however, some applications where a substantial amount of heat is generated by equipment either inside or outside the enclosure. In these cases, blower fans may be placed inside the enclosure to assist air circulation and to reduce “hot spots” near the Controller.

CAUTION: Do not bring outside air into the enclosure; it may introduce harmful contaminants or dirt.

ELECTRICAL NOISE

When the Mini-PLC-2/15 Controller is operating in a “noise-polluted” industrial environment, special consideration should be given to possible electrical noise interference. potential noise generators include inductive loads such as relays, solenoids, motors and motor starters when they are operated by “hard contacts,” such as pushbuttons and selector switches. in the case of reversing motor starters, hard contacts are wired to make each starter electrically as well as mechanically interlocked. In this case, suppression is needed at the device because of the hard contacts in the circuit with the load.

32

Suppression for noise generators may be necessary when these types of loads are connected as output devices of when connected along the same AC line which brings in power to the Mini-PLC-2/15 Controller.

A suggested electrical noise suppression unit for small AC devices (i.e, relays, solenoids, and starters up to NEMA Size 1) is shown in Figure 3.1. For larger contractors of NEMA Size 2 and above, a parallel varistor for transient voltage limitation is needed in addition to the RC network shown in Figure 3.2 and Figure 3.3. DC relays are suppressed by freewheeling diodes as shown in Figure 3.4.

Figure 3.1

Suppression for Small AC Inductive Load

Typical

120V AC

0.5

Discrete Component Equivalent

Allen–Bradley surge Suppressors: Cat. No. 1691–N2: General Purpose Cat. No. 599–K04: Bulletin 509 Starters Cat. No. 700–N5. N9 N24: 700 N Relays Cat. No. N10: Bulletin 709 Starters

Chapter 3

Assembly and Installation

220

Ω

10109–I

Figure 3.2 T

ypical Suppression for 3Phase Inductive Load

240/480V AC

CR5

µ f 220 Ω

0.47

Discrete Component Equivalent (3 Required)

Electrocube Part No. 1676–13 (3 Required)

10110–I

33

Chapter 3

Assembly and Installation

Figure 3.3

ypical Suppression for Large AC Inductive Load

120V AC

CR4

Electrocube Part No. RG167614

0.47

V130 LA1

Discrete Component Equivalent

General Electric MOV (Metal Oxide Varistor)

220

Figure 3.4 T

ypical Suppression for Small DC Inductive Load

PIV (Peak Inverse Voltage) rating of diode must be at least twice the applied DC voltage

V DC

10111I

10112-I

34

All possible sources of noise should be suppressed. Best results are achieved when the noise-suppressing networks are connected as closely as possible to the “noisy” device.

Chapter 3

Assembly and Installation

CONSTANT VOLTAGE TRANSFORMER

In applications where the AC line is especially unstable and subject to unusual variation, a constant voltage transformer can be used to stabilize the input voltage to the System Power Supply as well as the input voltage to the user devices.

A constant voltage transformer compensates for voltage changes at its input to maintain a steady voltage at its output. If a constant voltage transformer is required, it must be connected to the System Power Supply and all input devices connected to the Mini-PLC-2/15 Controller. Output devices should be connected on the same AC line, but not necessarily after the constant voltage transformer.

The constant voltage transformer must have a sufficient power rating for its load. The transformer power rating for the System Power Supply should be at least 225VA (volt-ampere).

Determining the proper size transformer must be based on several factors:

1. The user must determine the System Power Supply power requirement

from the nameplate or product specifications. The power requirement for the 1771-P1 Power Supply is 75 VA.

2. Determine total power requirement of inputs drawing power from this

transformer. Add worst case power requirement of output devices which will also draw power from this transformer. When output devices are connected, the transformer size is substantially increased.

3. Add input device power requirement and output device power requirement

(only those connected to the transformer secondary). Multiply the Power Supply VA rating by 3. Add this figure to the input/output device requirement.

These calculations determine the proper transformer size, allowing ample power to be delivered to the Power Supply throughout the entire AC cycle, and provide the necessary power for I/O devices.

NOTE: If the output devices connected to the transformer are motors follow the manufacturer’s transformer specifications. Some manufacturers recommend a reserve capacity of 6 to 8 times the motor VA requirement to handle starting current surges.

35

Chapter 3

Assembly and Installation

Enclosure

Considerations

An enclosure is usually provided by the user for housing the Mini-PLC-2/15 Controller. The enclosure is the primary means of protecting the Controller from atmospheric contaminants (oil, moisture, conductive dust or particles, or any corrosive or otherwise harmful airborne substance). Standards established by the National Electrical Manufacturer’s Association (NEMA) define enclosure types based upon the degree of protection the enclosure provides the components mounted inside. In general, an enclosure which conforms to the NEMA standard for Type 12 enclosures is preferred for solid state control devices.

The enclosure should be mounted in a position which allows the doors to be opened fully and allows access to wiring and components for testing or troubleshooting. Also important is the accessibility to a disconnect device in the enclosure.

The Mini-PLC-2/15 Controller requires a minimum of 8 inches of “working depth” in the enclosure. Working depth is the distance from the rear of the Chassis when mounted in the enclosure to the inner-most surface of the enclosure door when closed. This would take into account print pockets mounted on the door. Carefully examine the vendor’s data sheets for print pockets mounted on the door and stand off measurements when calculating the working depth of an enclosure.

Component

Spacing Considerations

Mini-PLC-2/15 Controller components must be spaced sufficiently from other equipment and the enclosure walls to allow convection cooling. Convection cooling draws a vertical column of air upward over the Controller module surfaces. To keep the Controller modules within the specified temperature limits, this cooling air, drawn in at the base of the Controller, must not exceed

C (1400F). Because of this vertical flow of air, the obstructed vertical

spacing above and below the Controller components is important.

The temperature of the air must not exceed 60

C (1400F) at any point immediately below any chassis. The failure rate of the semiconductor devices will increase significantly if the temperature is raised above 60)C.

The temperature will tend to be higher toward the top of the enclosure. Factors which determine the level at which the temperature will be 60

C include the size of the enclosure, the power dissipation within the enclosure, and the temperature of the air outside the enclosure.

The following rules apply to the placement of Mini-PLC-2/15 Controller components in relation to each other. Figure 3.5 and Figure 3.6 illustrate the spacing recommendations for two Power Supply mounting configurations.

36

Chapter 3

Assembly and Installation

Rule 1 - Allow at least 6 vertical inches above and below all Controller components. when more than one Controller is mounted in an enclosure, allow at least 6 vertical inches between Controllers. Do not mount any component above a 60

Rule 2 - Allow at least 4 horizontal inches on the sides of each Controller component. when two or more Controllers are mounted in the same horizontal plane, allow at least 6 horizontal inches between them.

Rule 3 - Allow at least 2 inches between the Controller and the wiring duct or terminal strips.

Rule 4 - When the Power supply is mounted separately, it cannot be mounted below the Processor.

Figure 3.5 Minimum Component Spacing Requirements (Power Supply Mounted to I/O Chassis)

C air temperature level.

(10.16cm)

Area reserved for Disconnect, Constant Voltage Transformer, Control Relays Motor Starters or other User Devices.

ЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙЙ

(15.24cm)

(5.08cm)

(10.16cm)

(5.08cm)

(15.24cm)

Wiring Duct

10113I

37

Chapter 3

Assembly and Installation

General Grounding Information

Grounding is an important safety measure in electrical installations. With solid state control systems, grounding has added value because it helps to reduce the effects of noise due to electromagnetic noise interference (EMI).

Allen-Bradley Programmable Controller components and their enclosures must be properly grounded. All applicable Codes and Ordinances should be observed when wiring the Controller.

The grounding path for the Controller components and their enclosures should be provided through a grounding electrode conductor to earth ground, the grounding electrode system. In this document, earth ground is defined as the central ground for all electrical equipment and AC power within any facility. All ground connections must be permanent and continuous to provide a low-impedance path to earth ground for induced noise current and/or fault currents.

An authoritative source for grounding requirements is the National Electrical Code published by the National Fire Protection Association of Boston, Massachusetts. Article 250 of the Code provides such data as the size and types of conductors and methods of safely grounding electrical components. Local Codes and Ordinances dictate which grounding method is permissible. See Publication 1770-980 for a discussion of general grounding and field wiring practices.

38

Chapter 3

Assembly and Installation

(10.16cm)

(15.24cm)

(10.16cm)

Figure 3.6 Minimum Supply)

(15.24cm)

Component Spacing Requirements (Separately Mounted Power

Area reserved for Disconnect, Constant Voltage Transformer, Control Relays Motor Starters or other User Devices.

ЙЙЙЙЙЙЙЙЙЙЙ

(5.08cm)

(10.16cm)

(5.08cm)

(15.24cm)

Wiring Duct

10114I

PC Component Grounding

The recommended configuration for grounding Allen-Bradley Programmable Controller components within an enclosure is illustrated in Figure 3.7. Bare metal contact is required to ensure that good electrical contract has been established between Controller components, the enclosure back panel, and the enclosure. Paint or other non-conductive finishes must be scraped from the back panel and Controller components where contact is made with the component mounting bolts, nuts, or welded studs. An 8-gauge copper wire, or larger, should be used to connect each component in the enclosure. Connections should be made to the mounting bolts or studs on only one mounting bracket of the component’s chassis (Figure 3.7).

39

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