Category: Industry Trends

How Does It Work?

Monitoring Axis Position

The module has four LDT inputs. You configure each axis for an LDT

with a Pulse Width Modulated output (DPM) or a Start/Stop output

(RPM) by changing axis configuration parameters.

Controlling Axis Output

The module is a targeting controller: every two milliseconds its microprocessor

updates TARGET POSITION and target SPEED values. For

point-to-point moves, TARGET POSITIONS are generated so that

resulting speed, accelerations, and decelerations follow either a

trapezoidal or s-curve profile.

The MODE, ACCELERATION, DECELERATION, SPEED, and

COMMAND VALUE (requested position) are used to generate the

profile. You send these command words to the module through the

processor’s output image table. You may change them “on-the-fly“

while the axis is moving.

The module compares ACTUAL POSITION with TARGET POSITION to

determine position error. Every update, it uses the position error to adjust

drive output. PID gains are adjustable and can be applied selectively.

Why Use This System?

Because you can interact quickly and easily with the module’s control of

axis motion via the Hydraulic Configurator, this control system has

these benefits:

• faster setup and tuning of axes – the Hydraulic Configurator lets you

quickly set up and tune each axis independent of your ladder program.

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

• smoother operation for longer machine life – you can profile accelerations

and decelerations of the hydraulic actuator to limit pressure spikes

• faster change-over to new parts – you can store setups (configuration

parameters) for quick an accurate change-over between parts

The module compares ACTUAL POSITION with TARGET POSITION to

determine position error. Every update, it uses the position error to adjust

drive output. PID gains are adjustable and can be applied selectively.

The module also provides two different feedforward algorithms;

EXTEND/RETRACT FEEDFORWARD, and EXTEND/RETRACT

ACCELERATION FEEDFORWARD. These feedforward terms provide

additional drive output to help the axis follow the target, freeing the

PID loop to correct for system nonlinearity and changes in load.

Environnements dangereux

Les produits marqués « CL 1, DIV 2, GP A, B, C, D » ne conviennent qu’à une

utilisation en environnements de Classe I, Division 2, Groupes A, B, C, D

dangereux et non dangereux. Chaque produit est livré avec des marquages sur sa

plaque d’identification qui indiquent le code de température pour les

environnements dangereux. Lorsque plusieurs produits sont combinés dans un

système, le code de température le plus défavorable (code de température le plus

faible) peut être utilisé pour déterminer le code de température global du système.

Les combinaisons d’équipements dans le système sont sujettes à inspection par les

autorités locales qualifiées au moment de l’installation.

WARNING !

DANGER D’EXPLOSION

• Coupez l’alimentation ou vérifiez que l’environnement est

classé non dangereux avant de débrancher l’équipement.

• Coupez l’alimentation ou vérifiez que l’environnement est

classé non dangereux avant de débrancher les connecteurs.

Fixez tous les connecteurs externes reliés à cet équipement

à l’aide de vis, loquets coulissants, connecteurs filetés ou

autres moyens fournis avec ce produit.

• La substitution de composants peut rendre cet équipement

impropre à une utilisation en environnement de Classe I,Division 2.

• Le câblage doit être conforme à l’article 501-4(b) du code

national de l’électricité aux Etats-Unis et aux réglementations locales en vigueur.

Overview

Install your power supply using these installation instructions. The only tools you

require are flat head (1/8”) and Phillips head (1/4”, #2) screwdrivers.

ATTENTION !

Electrostatic discharge can damage integrated circuits or

semiconductors if you touch backplane connector pins. Follow

these guidelines when you handle the power supplies.

• Touch a grounded object to discharge static potential.

• Do not touch the backplane connector or connector pins.

• Do not touch circuit components inside the power supply.

• Use a static-safe work station, if available.

• Keep the power supplies in their static-shield packaging

when not in use.

Hazardous Location Considerations

Products marked CL1, DIV 2, GP A, B, C, D are suitable for use in Class I, Division

2, Groups A, B, C, D or nonhazardous locations only. Each product is supplied with

markings on the rating nameplate indicating the hazardous location temperature

code. When combining products within a system, the most adverse temperature

code (lowest T number) may be used to help determine the overall temperature

code of the system. Combinations of equipment in your system are subject to

investigation by the local authority having jurisdiction at the time of installation.

If open circuit detection is enabled, the module tests for an open-circuit

condition. If it detects an open-circuit, over-range, or under-range

condition, the module sets a unique bit in the channel status word

and causes the channel status LED to flash.

The SLC processor reads the converted thermocouple or millivolt data

from the module at the end of the program scan, or when

commanded by the ladder program. After the processor and module

determine that the data transfer was made without error, the data can

be used in your ladder program.

Module Operation

The module’s input circuitry consists of eight differential analog

inputs, multiplexed into an A/D convertor. The A/D convertor reads

the analog input signals and converts them to a digital value. The

input circuitry also continuously samples the CJC sensors and

compensates for temperature changes at the cold junction (terminal block).

Hardware Features

The module fits into any single slot for I/O modules in either an SLC

500 modular system or an SLC 500 fixed system expansion chassis

(1746-A2), except the zero slot which is reserved for the processor. It

is a Class 1 module using 8 input words and 8 output words.(2)

The module contains a removable terminal block providing

connections for eight thermocouple and/or analog input devices. On

the terminal block are two cold-junction compensation (CJC) sensors

that compensate for the cold junction at ambient temperature. It

should also be noted there are no output channels on the module.

Configure the module with software rather than with jumpers or switches.

IMPORTANT

There is a jumper (JP1) on the circuit board. The

module is shipped with the jumper in the up

position as illustrated below. Do not change the

position of JP1. The jumper is used for test purposes

only.

System Operation

At power-up, the thermocouple module performs a check of its

internal circuits, memory, and basic functions. During this time the

module status LED remains off. If no faults are found during the

power-up diagnostics, the module status LED is turned on.

After power-up checks are complete, the thermocouple module waits

for valid channel configuration data from your SLC ladder logic

program (channel status LEDs off). After configuration data is written

to one or more channel configuration words and their channel enable

status bits are set, the channel status LEDs go on and the

thermocouple module continuously converts the thermocouple or

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

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

the module for a fault condition, i.e. open 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 blinks.

The SLC processor reads the converted thermocouple or millivolt data

from the module at the end of the program scan, or when

commanded by the ladder program. The processor and thermocouple

module determine that the backplane data transfer was made without

error, and the data is used in your ladder program.

Module Operation

The thermocouple module input circuitry consists of four differential

analog inputs multiplexed into a single analog-to-digital (A/D)

convertor. The mux circuitry also continuously samples the CJC A and

CJC B sensors and compensates for temperature changes at the cold

junction (terminal block). The figure on the following page shows a

block diagram for the analog input circuitry.

The A/D convertor reads the selected input signal and converts it to a

digital value. The multiplexer sequentially switches each input

channel to the module’s A/D convertor. Multiplexing provides an

economical means for a single A/D convertor to convert multiple

analog signals. However, it does affect the speed at which an input

signal can change and still be detected by the convertor.