Lauer Starline LCA 300/320/325 Text Display Application Guide

Lauer Starline LCA 300/320/325 Text Display Application Guide

Product Overview and Positioning

The Lauer Starline series text displays LCA 300, LCA 320, and LCA 325 are small human-machine interface solutions for industrial automation. They have become an economical tool for machine equipment status monitoring and operation with their compact size (LCA 300 is only 216 × 84 × 57mm), clear LCD display, and powerful communication capabilities. This series can display up to 1024 messages, support multiple languages, and can be adapted to almost all mainstream PLC brands through simple parameter configuration.

LCA 300 is equipped with a 2-line x 40 character display, while LCA 320/325 provides a 4-line x 40 character display (LCA 325 additionally integrates a printer interface). All models are equipped with 7 composite function/control keys and 1 Shift switch key, with a front panel protection level of IP65, suitable for harsh industrial environments. Its configuration software LCAPRO runs in a DOS environment and downloads project data to the device EEPROM through programming cable LCA 733, enabling rich text and variable display without programming. This article is based on the official technical manual, systematically sorting out the installation, configuration, communication protocol, and variable application points to help engineers quickly master this classic HMI tool.

Installation and electrical connection

2.1 Power supply requirements

LCA 300/320/325 requires 24V DC ± 20% power supply, with a typical power consumption of about 300mA (at 24V), maximum not exceeding 28.8V, and minimum not less than 19.2V. The power terminal is a 2-pin RIA pluggable type, allowing a wire diameter of 2mm ². The equipment must be powered by a protective extra low voltage (PELV) that complies with VDE 0551 standards, and it is recommended to ground 0V on the power side (according to VDE specifications) to optimize noise resistance. Short term voltage drop (up to 20ms) will not affect normal operation.

2.2 Grounding and anti-interference measures

The protective conductor (PE) is isolated from 0V inside the equipment, and the PE is connected to the interface casing. To achieve optimal immunity, the chassis must be grounded with a grounding wire (4mm ²) as short as possible. The following general anti-interference measures are crucial for stable operation:

The power line and signal line are separately laid in different cable trays

Maintain a safe distance of at least 250mm from the interference source

Contactors and relay coils need to be connected in parallel with freewheeling diodes or RC absorption circuits

Avoid using fluorescent lamps for lighting inside the control cabinet

Shielded signal line with both ends grounded, and if necessary, lay equipotential bonding conductors (≥ 10mm ²)

Install a power filter in front of strong interference equipment such as frequency converters

2.3 Mechanical Installation

The size of the front panel opening varies depending on the model (see technical parameters for details), with LCA 300 weighing approximately 450g and LCA 325 weighing approximately 950g. During installation, it is necessary to ensure that the sealing ring is correctly positioned to maintain IP65 protection. There are:

1A slow melting glass fuse tube

25 pin Sub-D female socket (RS232/TTY, used for PLC communication and programming)

15 pin Sub-D socket (RS422/485, only LCA 300.1/320.1/325.1 models)

9-pin Sub-D female socket (printer interface, LCA 325 only)

Contrast adjustment potentiometer (CONT)

Programming mode jumper (PROG/AUTO)

LCAPRO configuration software

LCAPRO is the only authorized configuration tool in the LCA series, running in MS-DOS or DR-DOS environments, requiring a PC to have at least one serial port and 3MB of hard disk space. Its main functions include:

Interactively generate all text (idle page, message page, operation page, help page)

Define variables and associate them with the PLC data area

Select PLC driver (for different brands of PLCs)

Generate project documentation

Upload existing data records from LCA (for on-site service convenience)

Supports multiple languages (Dutch, English, French, German, Italian)

After configuration is complete, connect the PC serial port to the 25 pin interface of LCA through programming cable LCA 733, and download project data (including text, variable definitions, drivers, firmware) to the device EEPROM. Attention: Only LCAPRO can be used to create projects, other software may cause equipment and PLC failures.

Communication principles and data area structure

The communication between LCA and PLC adopts a concise "shared data area" model: LCA writes operation requests and key states to specific bytes of PLC, while reading message bits and variable values from PLC. The communication is physically connected by an adapter cable (LCA 7xx series).

4.1 System Byte Allocation (B0~B255)

B0: Operation page number (0~255), written into PLC by LCA

B1: Key status+heartbeat signal (Bit0 is periodically set to 1 by LCA for PLC to detect communication status)

B2: Printer status (LCA 325 only, Bit0=Hardcopy completed, Bit1=Printing, Bit2=Printer ready)