Category: A-B

General Diagnostic Features

The RTD module contains diagnostic features that can be used to help you

identify the source of problems that may occur during power up or during

normal channel operation. These power-up and channel diagnostics are

explained in Chapter 6. Module Diagnostics and Troubleshooting.

The RTD module communicates to the SLC 500 processor through the

parallel backplane interface and receives +5V dc and +24V dc power from the

SLC 500 power supply through the backplane. No external power supply is

required. You may install as many RTD modules in your system as the power

supply can support, as shown in the illustration below.

System Overview

Each individual channel on the RTD module can receive input signals from 2.

3 or 4-wire RTD sensors or from resistance input devices. You configure each

channel to accept either input. When configured for RTD input types, the

module converts the RTD readings into linearized, digital temperature

readings in °C or °F. When configured for resistance inputs, the module

provides a linear resistance value in ohms.

Description

The RTD module supplies a small current to each RTD connected to the

module inputs (up to 8 input channels). The module provides on-board

scaling and converts RTD input to temperature (°C, °F) or reports resistance

input in ohms.

Each input channel is individually configurable for a specific input device.

Broken sensor detection (open- or short-circuit) is provided for each input

channel. In addition, the module provides indication if the input signal is

out-of-range. For more detail on module functionality, refer to the subsection

entitled System Overview later in this chapter.

General Diagnostic Features

The RTD module contains diagnostic features that can be used to help you

identify the source of problems that may occur during power up or during

normal channel operation. These power-up and channel diagnostics are

explained in Chapter 6. Module Diagnostics and Troubleshooting.

The RTD module communicates to the SLC 500 processor through the

parallel backplane interface and receives +5V dc and +24V dc power from the

SLC 500 power supply through the backplane. No external power supply is

required. You may install as many RTD modules in your system as the power

supply can support, as shown in the illustration below.

Overview

This chapter describes the 8-channel 1746-NR8 RTD/Resistance Input

Module and explains how the SLC controller gathers RTD (Resistance

Temperature Detector) temperature or resistance-initiated analog input from

the module. Included is:

· a general description of the module’s hardware and software features

· an overview of system operation

For the rest of the manual, the 1746-NR8 RTD/Resistance Input Module is

referred to as simply the RTD module.

The RTD module receives and stores digitally converted analog data from

RTDs or other resistance inputs such as potentiometers into its image table for

retrieval by all fixed and modular SLC 500 processors. An RTD consists of a

temperature-sensing element connected by 2. 3. or 4 wires that provide input

to the RTD module. The module supports connections from any combination

of up to eight RTDs of various types (for example: platinum, nickel, copper, or

nickel-iron) or other resistance inputs.

System Operation

Tle power

• Module operation

• Error (module error and channel error)

Cycle Power

When you cycle the module’s power, the RTD module checks its

internal circuits, memory, and basic functions via hardware and

software diagnostics. During this time the module status LED indicator

remains off. If no faults are found during the diagnostics, the module

status LED indicator is on.

After the checks are complete, the RTD module waits for valid

channel configuration data from your SLC ladder logic program

(channel status LED indicators off). After configuration data is written

to one or more channel configuration words and their channel enable

bits are set by the user program, the channel status LED indicators go

on and the module continuously converts the RTD or resistance input

to a value within the range you selected for the enabled channels. The

module is now operating in its normal state.

Each time a channel is read by the module, that data value is tested by

the module for a fault condition, for example, open circuit, short

circuit, over range, and under range. If such a condition is detected, a

unique bit is set in the channel status word and the channel status

LED indicator blinks, indicating a channel error condition.

Description

The RTD module receives and stores digitally converted analog data

from RTD units or other resistance inputs such as potentiometers into

its image table for retrieval by all fixed and modular SLC 500

processors. An RTD module consists of a temperature-sensing element

connected by two, three, or four wires that provide input to the RTD

module. The module supports connections from any combination of

up to four RTD units of various types (for example: platinum, nickel,

copper, or nickel-iron) or other resistance inputs.

The RTD module supplies a small current to each RTD unit connected

to the module inputs (up to 4 input channels). The module provides

on-board scaling and converts RTD unit input to temperature (°C, °F)

or reports resistance input in ohms.

Each input channel is individually configurable for a specific input

device. Broken sensor detection (open- or short-circuit) is provided

for each input channel. In addition, the module provides indication if

the input signal is out-of-range.

Overview

This chapter describes the four-channel 1746-NR4 RTD/Resistance

Input Module and explains how the SLC controller gathers RTD

(Resistance Temperature Detector) temperature or resistance-initiated

analog input from the module.Included is:

• a general description of the module’s hardware and software features.

• an overview of system operation.

For the rest of the manual, the 1746-NR4 RTD/Resistance Input

Module is referred to as simply the RTD module.

Each time a channel is read by the module, that data value is tested by

the module for a fault condition, for example, open circuit, short

circuit, over range, and under range. If such a condition is detected, a

unique bit is set in the channel status word and the channel status

LED indicator blinks, indicating a channel error condition.

The SLC processor reads the converted RTD or resistance data from

the module at the end of the program scan or when commanded by

the ladder program. The processor and RTD module determine that

the backplane data transfer was made without error and the data is

used in your ladder program.

(1) To maintain group isolation provided by 32-point I/O modules, use a 1492 terminal block that provides group isolation. 

Consult 1492 documentation or your Allen-Bradley Sales Office for additional information.

(2) Maximum user cable length is dependent on how much voltage drop (current x (ohms/ft.) x (feet)) the user’s system can 

tolerate. The user’s system should take into account the minimum turn-on voltage required by external loads connected to 

the 32-point output modules and all of the voltage drops associated with wiring to and from the load, terminal blocks, 

power sources and the module itself.

Assembly Procedure for Crimp Contacts

The following details the assembly procedure for the crimp type contacts.

1. Strip the wire insulation as shown in Figure 1.

2. Insert the wire up to the wire stop as shown in Figure 2.

3. Crimp with DDK crimp tool 357J-5538. Equivalent Amp part numbers are: 

pin – 87666-2, connector – 102387-9, and crimp tool – 90418-1.

If a crimp tool is not available, used the following crimping procedure:

a. Crimp the wire barrel around the wire using a small needle nose pliers.

b. Crimp the insulation barrel around the wire insulation using a small 

needle nose pliers.

c. Solder wire and wire barrel together.

4. After completing above assembly, insert the cable into the socket housing as 

shown in Figures 3 and 4. Check to make sure that the tang, shown as “A” in 

Figure 4, is properly latched by gently pulling on the wire.

Overview

The 1746-N3 Connector Kit is used to terminate a cable which connects field I/O 

devices to SLC 500 32-point I/O modules. The kit contains a keyed 40-pin socket 

header with 45 socket crimp type contacts.

The N3 connector is compatible with 32-point I/O modules, catalog numbers 

1746-IB32, -IV32, -OB32, -OB32E -OV32 and Allen-Bradley 1492-IFM40 terminal 

blocks (see illustration). When the 1746-N3 is used to terminate the I/O cable at the 

1492-IFM40 end, it should be wired in a straight-through manner (i.e. pin 1 to pin 1, 

pin 2 to pin 2, etc.). For additional instructions, refer to the wiring instructions 

provided with your 32-point I/O module.

Use 24 AWG wire with the 1746-N3. Maximum wire length to the user terminal 

block is 10 meters for inputs and 3 meters for outputs with 7-strand, 24 AWG wire.

Wiring Notes

• Ground cable shields at one end only.

• Isolate signal wiring from power lines and sources of electrical noise.

• Do not exceed 10V dc on any input terminal.

• Outputs +Exc, +T/R, and -T/R must have a minimum load of 1K ohms.

referenced to analog common.

Module I/O

Inputs

The module has two independent channels that you configure to process 

signals from machine sensors (default) or from the SLC output image table 

across the backplane.

Outputs (Summary Data)

The module processes a frame of summary data for each molding cycle, 

and alternately makes available the previous frame for display. It does this 

for channels 1 and 2. Your ladder logic can read summary data from the 

module’s M0/M1 files. You can observe summary data displayed on a PC 

equipped with DARTWin software. The PC must be linked to the module 

with DARTNet network from RJG Technologies, Inc.

Configure the SLC Processor (including I/O, M0/M1, and G file)

This procedure is based on RSLogix500 programming software, version 

2.0 or later. For other software, the procedure may vary.

Configure the SLC processor, I/O, size of M0/M1 files, and G file offline 

to match your system layout. 

1. With the File pull-down window, open the ladder file associated with 

this project, or create a project (ladder file) for it.

2. If you have not already done so, select the Controller Properties icon 

and launch it. Then select/enter the type of SLC processor.

3. Select the I/O Configuration icon and launch it. Then select/enter:

A. Slot number in the I/O chassis for this module

If using this module in a Pro-Set 200 Injection Control System, 

assign this module to slot 7.

B. Module ID (12935), entered under “Other” in the I/O Module window.

Important: When you enter the module ID, the processor automatically 

reserves the required number of I/O image table words. The location of 

those words in the I/O image table is determined by the module’s slot 

location in the I/O chassis. Slot location is a required addressing unit. 

For example, I:e.6 locates the 6th word in the block of input image table 

words assigned to the module in slot e that you entered in A, above. 

C. If you have not already done so, enter the size of I/O chassis and the type of power supply.

4. Select the Adv Configuration icon and launch it.

Then select/enter:

A. Length of M0/M1 files at 106 words, each (listed in section 11).

B. Length of G file at 94 words.

What the module does

The module processes and extracts cyclic injection molding data for 

display on your PC, and responds to alarms that you set to monitor 

critical molding parameters. 

When used with the Pro-Set 200 Injection Molding Control System, 

the module helps you:

• achieve a quicker setup time to obtain optimum part quality

• maintain that quality over the production run

The module and associated DARTWin software help you to set up the 

injection molding machine for optimum performance. Then you set 

alarm limits on critical parameters to detect deviations while making 

parts. You can also set a critical mold pressure to transfer the injection 

process each machine cycle. 

The module is designed for use with the SLC 5/03 (or later) processor. 

You program it to interface with the injection molding machine. The 

module has two independent channels to accept analog pressure inputs 

from sensors or from the SLC processor across the backplane. It 

returns alarm signals and processed molding parameters to the SLC 

processor for your application programming and to your PC for 

graphic display. We show the module in a typical Pro-Set 200 system.