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)

B3: Key code (Bit0~2 is the encoding of keys 1~7, Bit6=Shift key state, Bit7=internal function activation flag)

B4~B5: LED control (each key LED is controlled by two bits: OFF/ON/flashing/reverse flashing)

B6: Data recording/language selection (Bit0=0 selects record 1,=1 selects record 2)

B7: Message mode and priority enable (see below for details)

B8: Printer control (LCA 325, Bit0 triggers hard copy, Bit1 enables message printing)

B9: Idle text number (0~255)

B10~B137: Message area (1024 message bits, corresponding to message text 0~1023)

B138~B255: Variable area (for users to define actual and preset values)

4.2 Message bits and text

Each message bit corresponds to one message text (up to 1024 messages). The conversion rule between message bit address and text number is: bit b of even address a corresponds to message number a × 8+b; bit b of odd address a corresponds to message number (a-1) × 8+b+128. For example, byte 34.2 corresponds to message 202. When the PLC displays message position 1, the corresponding message text is immediately displayed; If reset to zero, the text will disappear.

4.3 Variable Area

B138~B255 (and unused message areas) can be used to define variables. Variables are divided into actual values (read-only) and preset values (editable and written back to PLC). Variable formats include BIT, STRING, BCD, BIN, VBIN, WORD, TIMER, ASCII, etc.

Detailed explanation and application examples of variable formats

5.1 BIT Variables

Associate two strings with the 0/1 state of a certain bit. For example, address 160.1 defines VAR1, displaying "WITH" when Bit=0 and "WITH" when Bit=1. Multiple BIT variables can be embedded in the same message text to achieve state combination display.

5.2 STRING Variables

Map 256 values (0~255) of a byte to 256 strings. For example, for the STATUS variable at address 163, a value of 0 indicates "SETTING UP", 1 indicates "SINGLE STEP", 2 indicates "SEMI-AUTMATIC", 3 indicates "MATIC", and so on. After embedding this variable in the message text, the display text can be automatically switched based on the PLC byte value.

5.3 BINARY Variables (BIN/VBIN)

Convert binary values in PLC to decimal display. Support:

BIN-1 (byte) and BIN-2 (word): unsigned numbers

VBIN-1/VBIN-2: signed numbers

Can set integer, decimal, minimum/maximum values, and leading zeros display. For example, if a temperature variable (address 255) is defined in VBIN-1 format, with 2 integers and 1 decimal place, and a range of -128~+127, the corresponding PLC value will be displayed in the form of "25.5 ℃".

5.4 BCD Variables

Split the BCD encoded bytes in the PLC into 1-2 digits for display. Suitable for displaying values from BCD dip switches or encoders. For example, combining address 159 (low 4 bits) and 160 (high 4 bits) to display as two digits.

5.5 ASCII Variables

Directly display ASCII codes in PLC bytes as characters. Suitable for displaying text information such as operator name and batch number. Each address 163~166 stores one ASCII character, which is displayed as a 4-character name in combination. Note: ASCII variables must be pre-set with non-zero valid values and cannot be 00.

Priority management

LCA 300/320/325 adopts a 5-level priority to determine the display content:

Priority name trigger condition

0 (lowest) idle priority. Display idle text when there are no other activities

1. Information priority message bit triggered and attribute is "Information"

2. Fault priority message triggered with attribute "Fault"

3. Operation priority: Press the EDIT key to enter

4 (highest) editing priority automatically activated when editing variables

Users can control the enable/disable of each priority through B7:

B7.3=0: Enable operation priority; =1 Prohibited

B7.6=0: Information priority enabled; =1 Prohibited

B7.7=0: Fault priority enabled; =1 Prohibited

The message mode is controlled by B7.4~B7.5: 00=display the last message, 01=display the first message, 10=loop display.

Button and LED functions

The LCA equipment is equipped with 7 composite function/control keys and 1 Shift switch key (PLC/LCA).

7.1 External mode (PLC LED on)

The key codes are transmitted to the PLC through B3.0~B3.2 for the PLC program to directly respond to key actions. B3.6 Set to 1 when the Shift key is pressed.

7.2 Internal mode (LCA LED on)

The buttons are used for internal operations:

←/→: Select the operation page; Move the cursor while editing variables

↑/↓: Page up to browse messages/help; Increase or decrease variable values during editing

ENTER: Enter editing mode; Confirm variable modification and write it to PLC

EDIT: Display an overview of the operation page; Exit editing mode

HELP: Display the corresponding help text for the current page

PLC/LCA: Switching between internal and external modes

7.3 LED Control

Each function key is equipped with a green LED, which is controlled by a combination of B4 (ON/flashing) and B5 (anti flashing/ON) to achieve four states: OFF, ON, FLASHING (75% on), and INVERSE FLASHING (25% on). The system status LED includes ERR (Fault/Communication Interruption), PLC (External Mode), LCA (Internal Mode).

Printer Function (LCA 325)

LCA 325 integrates printer interface, supporting hard copy and message printing functions.

8.1 Printer Parameters (LCAPRO Configuration)

Handshake protocol: NONE, XON/XOFF, RTS-CTS

Baud rate: 1200~9600

Data bits: 7/8 bits, stop bit 1/2 bits, verify NONE/EVENT/ODD

Output direction: UP (last line output first) or DOWN

Initialization string: default "0D 0A" (carriage return, line break)

8.2 Printing Control (B8)

B8.0:0 → 1 triggers the hard copy (printing the current screen content), and after completion, B2.0 sets it to 1

B8.1: Set 1 to enable message printing, and all new messages will be automatically added to the printing queue; Set 0 to clear the queue

B2.1: Printing the logo

B2.2: Printer Ready Flag (valid in RTS-CTS mode)

Message printing adopts a row oriented approach, where variable values are read from the PLC only when the corresponding row is printed, ensuring real-time data.

Explosion proof application (Ex area)

LCA 300/320/325 can be pre configured for Ex Zone 1 or 2 (specified when ordering). Attention should be paid when using Ex Zone 2 (explosive gas only occasionally appears for a short period of time):

The front panel is made of polyester material, which may generate static electricity and can only be cleaned with a damp cloth

The power supply cable, interface cable, and EPROM card must be powered off before they can be plugged in and out

Installation must comply with VDE 0165

Ex Zone 1 requires PTB (German Federal Agency for Physical Technology) certification for use

Quick search for technical parameters

Parameter specifications

Supply voltage 24V DC ± 20%, approximately 300mA

Display LCA 300:2 × 40 characters; LCA 320/325:4 × 40 characters

Character height 5mm, 5 × 7 dot matrix

7 composite function keys+1 Shift key

LED 3 system LEDs+7 key internal LEDs

Maximum message capacity of 1024 messages

The maximum number of pages on the operation page is 256

Idle/Message/Help page, with a maximum of 32 lines per page

Memory 64KB Flash PROM

Variable formats BIT, STRING, BCD, BIN, VBIN, WORD, TIMER, ASCII

Protection level: front panel IP65, rear panel IP20

Working temperature: 0~+50 ℃

Weight LCA 300 is about 450g, LCA 325 is about 950g

Key points and common problems of engineering debugging

11.1 Debugging steps

Install the equipment and confirm that the power supply is 24V and the grounding is good.

Create a project using LCAPRO: Select PLC driver ->Define message text ->Define variables ->Configure printer (if needed) ->Generate data records.

Connect programming cable LCA 733, place the DIL jumper in the PROG position, and display the version number after power on.

Download the project to LCA EEPROM and restore the jumper to AUTO after completion.

Connect the PLC communication cable and observe the ERR LED: if it is constantly on, it indicates that communication has not been established; if it flashes, it indicates that communication has been established but interrupted; if it is off, it indicates normal communication.

Test message triggering, variable display, and editing functions.

11.2 Common Fault Handling

ERR LED always on: Check if the data record is valid, if the communication cable is correct, and if the PLC side interface parameters match.

Display garbled characters: Check if the character set selected in LCAPRO matches the BIOS version (BIOS ≥ 201.4 recommends using international character sets).

Variable display "00" or blank: Confirm that the variable address does not overlap with the message area, and ASCII variables need to be pre-set with non-zero values.

Unable to enter editing mode: Confirm B7.3=0 (operation priority enabled) and press the EDIT key to enter.

Printer not responding: Check if B8.1 is set to 1 and if the handshake protocol and baud rate match the printer.

Invalid data record switching: When switching records in B6.0, communication parameters are always read from record 1, and it is necessary to ensure that the configuration in record 1 is correct.