Category: A-B

Important: To minimize the adverse effects of ground loops, you must

isolate power supply and signal commons from earth ground as follows:

1. Connect power supply commons to IFM Com terminal (50), and

LDT commons to LDT Com terminals of the IFM terminal block.

Be sure that they are isolated from earth ground.

2. Connect the cable shield of the servo or proportional amplifier

output cable to a zero potential terminal inside the amplifier.

3. Use bond wires that are equal in size to signal wires.

4. When practical, use one power supply to power only your LDTs.

Connecting Outputs to Output Devices

Note: Follow manufacturer recommendations for shielding the output

cables of the proportional amplifier. Typically, pulse-width modulated

outputs radiate electrical noise originating from the +24V dc power

supply, so isolate the shields of the amplifier output cable to a 0V dc

connection inside the proportional amplifier.

You have a choice of three configurations to match your hydraulics:

• proportional amplifier integrated with a proportional valve

• servo amplifier and variable-volume pump or servo valve

• Allen-Bradley 1305 Drive and hydraulic pump

You may use either of the following output voltage ranges:

• 0-10V dc for an Allen-Bradley 1305 Drive or variable-volume pump

• –10 to +10V dc for a proportional or servo amplifier

If using servo valves, you must convert the module’s output from voltage to current.

Minimizing Interference

from Radiated Electrical

Noise

Important: Signals in this type of control system are very susceptible to

radiated electrical noise. The module is designed to detect loss-of-sensor

and sensor noise conditions for any of the four axes when position values

are lost or corrupted. The Hydraulic Configurator displays these

conditions in the Status word window. The resulting hard or soft stop

depends on how you configured autostop conditions. (See Hydraulic

Configurator, Config word, and click on autostop “Help“).

To minimize interference from radiated electrical noise with correct

shielding and grounding:

• Connect LDT cable shields and drive output cable shields (all

shields at one end, only) to IFM terminal block SH terminals, and

connect the IFM terminal block GND terminal (51) to earth ground.

• Keep LDT signal cables far from motors or proportional amplifiers.

• Connect all of the following to earth ground:

– power supply cable shields (one end, only)

– LDT flange, frame, and machine

– I/O chassis

– AC ground

• Use shielded twisted pairs for all connections to inputs and outputs.

• Run shielded cables only in low-voltage conduit.

• Place the SLC-500 processor and I/O chassis in a suitable enclosure.

What Is the

Hydraulic Configurator

The module is designed for use with the Hydraulic Configurator, a

software product that you can obtain from the Allen-Bradley website on

the Internet. The Hydraulic Configurator is an interactive executable

that lets you configure the module and tune its axes. With it, you can:

• configure axes and store configuration parameters

• tune each axis independent of the ladder program

• store multiple commands to initiate repetitive axis motion

• display a log of the last 64 motion commands sent to the module

• observe and/or store plots of each axis

• access help screens that explain and/or describe module features

Important: The Hydraulic Configurator saves considerable time when

tuning axes and troubleshooting faults. Thereafter, your ladder logic

sequences module operation with the machine.

What Is an

SLC-500 System?

The Allen-Bradley Small Logic Controller (SLC) system is a programmable

control system with an SLC processor, I/O chassis containing

analog, digital, and/or special-purpose modules, and a power supply.

The 1746-QS module occupies one slot of the I/O chassis and

communicates with the SLC processor over the backplane using 32

words in the SLC processor’s output image table and 32 words in the

input image table. The processor loads or reads the module’s

configuration parameters using M0 or M1 files, respectively. Your

ladder logic sequences synchronized axes movement with machine

operation. 

What Is the 1746-QS Module?

The 1746-QS Synchronized Axes Module provides four axes of

closed-loop synchronized servo positioning control, and lets you

change motion parameters while the axis is moving. The module has

four optically isolated inputs for signals from linear displacement

transducers (LDTs) and four optically isolated ±10 volt outputs that

interface with proportional or servo valve amplifiers.

The module’s microprocessor provides closed-loop control. The

module reads the axis position and updates the drive output every

two milliseconds, for precise positioning even at high speeds.

What Is the

Hydraulic Configurator

The module is designed for use with the Hydraulic Configurator, a

software product that you can obtain from the Allen-Bradley website on

the Internet. The Hydraulic Configurator is an interactive executable

that lets you configure the module and tune its axes. With it, you can:

• configure axes and store configuration parameters

• tune each axis independent of the ladder program

• store multiple commands to initiate repetitive axis motion

• display a log of the last 64 motion commands sent to the module

• observe and/or store plots of each axis

• access help screens that explain and/or describe module features

Important: The Hydraulic Configurator saves considerable time when

tuning axes and troubleshooting faults. Thereafter, your ladder logic

sequences module operation with the machine.

ATTENTION

!

Environment and Enclosure

This equipment is intended for use in a Pollution Degree 2

industrial environment, in overvoltage Category II applications

(as defined in IEC publication 60664-1), at altitudes up to

2000 m (6561 ft) without derating.

This equipment is considered Group 1. Class A industrial

equipment according to IEC/CISPR Publication 11. Without

appropriate precautions, there may be potential difficulties

ensuring electromagnetic compatibility in other environments

due to conducted as well as radiated disturbance.

This equipment is supplied as open type equipment. It must be

mounted within an enclosure that is suitably designed for those

specific environmental conditions that will be present and

appropriately designed to prevent personal injury resulting from

accessibility to live parts. The interior of the enclosure must be

accessible only by the use of a tool. Subsequent sections of this

publication may contain additional information regarding

specific enclosure type ratings that are required to comply with

certain product safety certifications.

See NEMA Standards publication 250 and IEC publication

60529. as applicable, for explanations of the degrees of

protection provided by different types of enclosure. Also, see

the appropriate sections in this publication, as well as the

Allen-Bradley Industrial Automation Wiring and Grounding

Guidelines, publication 1770-4.1. for additional installation

requirements pertaining to this equipment.

System Operation

At power-up, the module checks its internal circuits, memory, and

basic functions. During this time the module status LED remains off. If

the module finds no faults, it turns on its module status LED.

After completing power-up checks, the module waits for valid channel

configuration data from your SLC ladder logic program (channel status

LEDs are off). After channel configuration data is transferred and

channel enable bits are set, the enabled channel status LEDs turn on.

Then the channel continuously converts the thermocouple or millivolt

input to a value within the range you selected for the channel.

Each time the module reads an input channel, the module tests that

data for a fault, i.e. over-range or under-range condition. 

System Overview

The module communicates with the SLC 500 processor and receives

+5V dc and +24V dc power from the system power supply through

the parallel backplane interface. No external power supply is

required. You may install as many thermocouple modules in the

system as the power supply can support.

Each module channel can receive input signals from a thermocouple

or a mV analog input device. You configure each channel to accept

either one. When configured for thermocouple input types, the

module converts analog input voltages into cold-junction

compensated and linearized, digital temperature readings. The

module uses National Institute of Standards and Technology (NIST)

ITS-90 for thermocouple linearization.

When configured for millivolt analog inputs, the module converts

analog values directly into digital counts. The module assumes that

the mV input signal is linear.

General Description

This module mounts into 1746 I/O chassis for use with SLC 500 fixed

and modular systems. The module stores digitally converted

thermocouple/mV analog data in its image table for retrieval by all

fixed and modular SLC 500 processors. The module supports

connections from any combination of up to eight thermocouple/mV analog sensors.

Input Ranges

The following tables define thermocouple types and associated

temperature ranges and the millivolt analog input signal ranges that

each of the module’s input channels support. To determine the

practical temperature range of your thermocouple, refer to the

specifications in Appendix A.

General Diagnostic Features

The thermocouple/mV module contains diagnostic features that can

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 7. Module Diagnostics

and Troubleshooting.

System Overview

The thermocouple 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 thermocouple modules in your system as the power supply can support.

Each individual channel on the thermocouple module can receive

input signals from thermocouple sensors or mV analog input devices.

You configure each channel to accept either input. When configured

for thermocouple input types, the thermocouple module converts the

analog input voltages into cold-junction compensated and linearized,

digital temperature readings. The 1746-NT4 uses the National Bureau

of Standards (NBS) Monograph 125 and 161 based on IPTS-68 for

thermocouple linearization.

When configured for millivolt analog inputs, the module converts the

analog values directly into digital values. The module assumes that the

mV input signal is already linear.

Hardware Features

The thermocouple module fits into any single-slot, except the

processor slot (0), in either an SLC 500 modular system or an SLC 500

fixed system expansion chassis (1746-A2). It is a Class 1 module (uses

8 input words and 8 output words). It interfaces to thermocouple

types J, K, T, E, R, S, B, and N, and supports direct ±50 mV and ±100

mV analog input signals.

The module requires the use of Block Transfer in a remote configuration.

The module contains a removable terminal block providing

connection for four thermocouple and/or analog input devices. There

are also two, cold-junction compensation (CJC) sensors used to

compensate for offset voltages introduced into the input signal as a

result of the cold-junction, i.e., where the thermocouple wires connect

to the module wiring terminal. There are no output channels on the

module. Module configuration is done via the user program. There are

no DIP switches.