Month: July 2025

Obtaining the Ladder

Program Electronically

from BBS or the Internet

You can obtain ladder logic electronically and download it to your

SLC processor conveniently without the worry of data-entry errors.

About the Rockwell Bulletin Board System (BBS)

You can access the Rockwell Software Bulletin Board System (BBS)

by modem. Anyone is welcome. The BBS provides utilities, examples,

and technical information on Rockwell Software products and on

selected Allen-Bradley products.

• new users may:

– send and receive messages

– download General Access files

– upload files for review by technical support specialists

• verified customers may:

– search for new and existing files

– download files such as utilities, example programs, tech info

– access software bulletins

• subscribers to tech bulletins, DataDisc CD-ROM may:

– download tech bulletins of the Tech Bulletin Subscription series

User accounts are automatically generated online. We use our product

data base to verify BBS accounts at your initial log-in, and we adjust

your security level according to your support status. Should your

registration information change, you can update your account from the

“Configure System Defaults” menu.

Why Use This System?

Because you can change the speed of the hydraulic ram with extend

and retract profiles and store additional profiles (recipes) in data

table iNteger (N) files, this control system has these benefits:

• reduced cycle time – you can increase ram speed for faster operation

• reduced or eliminated pressure spikes and water-hammering for

smoother operation and less wear and tear on the machine –

you can profile accelerations and decelerations of the hydraulic ram

• energy savings – you can match the speed of the hydraulic pump

to the force that you need

• faster new-part change-over – you can store your setups and

minimize mechanical re-adjustments between parts

How Does It Work?

The 1746-QV module executes the extend and retract profiles that you

load to control the motion of the hydraulic ram. You can program up

to seven different voltages over the length of travel in both the extend

and retract directions to control how the ram accelerates or decelerates.

Each position setpoint triggers a corresponding voltage output in the

range of –10V to +10V dc that translates into speed. The LDT

provides high-speed position updates to the module for consistent and

repeatable motion.

What Are Typical Applications?

Use the 1746-QV module in an SLC-based system for low-cost

control of:

• hydraulic machinery

• simple (non-CNC) hydraulic presses

• diecasting machinery

• welder placement

• pneumatic actuators for clamping or placement

In addition, the module is designed to support standard proportional

amplifiers and retrofit into most existing hydraulic systems.

What Is the 1746-QV Module?

The 1746-QV module is part of an SLC-based open-loop control

system for controlling the speed and placement of an hydraulic ram.

The module accepts an input from a linear displacement transducer

(LDT) and motion profiles that you program into the SLC processor,

and varies its output in the range of 10V dc. The SLC processor

sends to the module a pair of extend and retract profiles that define

when to accelerate or decelerate hydraulic motion.

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-QV module interfaces your hydraulic ram

and position-monitoring device (LDT) to the ladder sequence in your

SLC processor. 

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.