Laumas TLM8 Ethernet TCP/IP Digital Weight Transmitter for Load Cells

Product Overview

The Laumas TLM8 is a high-precision digital weight transmitter and indicator designed for industrial weighing systems. It accepts up to 8 analog load cell inputs (350 Ω each) and converts the measured weight into digital data for transmission over Ethernet TCP/IP networks. This DIN-rail mounted device is ideal for silos, tanks, hoppers, and multi-vessel weighing applications where remote monitoring and integration with PLCs or SCADA systems is required. The TLM8 combines flexibility, accuracy, and industrial communication capabilities in a compact housing.

Key Specifications

• Model: TLM8

• Number of Load Cell Inputs: 8 (independent channels)

• Load Cell Supply: 5 VDC / 120 mA (shared for all channels)

• Input Sensitivity: 0.5 µV/d minimum

• Internal Resolution: 24-bit A/D converter (up to 16,000,000 counts)

• Linearity: < 0.005% of full scale

• Measurement Rate: Up to 100 conversions per second (programmable)

• Communication Protocol: Ethernet TCP/IP (Modbus TCP, Laumas ASCII)

• Display: 6-digit red LED (height 7 mm)

• Keypad: 3-button keyboard (function programming, zero, tare)

• Digital I/O: 2 inputs, 4 outputs (optocoupler isolated)

• Power Supply: 12-24 VDC (8 W max)

• Enclosure: ABS, IP40 (front panel IP65 when panel-mounted)

• Mounting: DIN rail or panel mounting (via optional kit)

• Operating Temperature: -10°C to +50°C

• Certifications: CE, RoHS

Multi-Channel Weighing Architecture

The TLM8 is specifically designed for applications requiring simultaneous weight acquisition from multiple independent load cell systems. Each of its 8 channels can be configured with its own calibration parameters, filters, and measurement units (kg, lb, t, etc.). This makes the TLM8 an efficient solution for multi-vessel batching, tank farm monitoring, and distributed weighing networks.

Ethernet TCP/IP and PLC Integration

The built-in Ethernet port supports both Modbus TCP and Laumas’ ASCII protocol, allowing seamless connection to PLCs (e.g., Siemens, Rockwell, Omron), PC-based SCADA systems, and industrial HMIs. The transmitter can act as a server on the network, providing weight data to multiple clients simultaneously. Real-time weight values, status bits (zero, tare, overload), and configuration parameters can be read or written via standard industrial Ethernet infrastructure.

High-Precision Measurement

Equipped with a 24-bit sigma-delta A/D converter, the TLM8 delivers excellent measurement stability and resolution (up to 1/16,000,000 internal counts). This high precision ensures accurate weight reading even with low-capacity load cells or under noisy environmental conditions. Digital filtering (moving average, median, FIR) can be applied to dampen vibrations and mechanical noise in dynamic filling or checkweighing applications.

Calibration and Configuration

Calibration can be performed directly via the front keypad (theoretical with mV/V, real weight with sample, or linearization up to 8 points per channel) or remotely using the free Laumas Configurator software over Ethernet/RS232. All calibration parameters are stored in non-volatile memory, ensuring data retention during power loss. The unit also supports digital tare, zero tracking, and auto-zero functions to maintain measurement accuracy over long periods.

Digital I/O for Local Control

Two optocoupler-isolated inputs (24 VDC) can be used for external pushbuttons (e.g., tare, print) or for remote start of weighing cycles. Four relay outputs (SPST, 30 VDC/1 A) can be configured as setpoints (high, low, within band) for direct control of valves, feeders, or alarms. This allows the TLM8 to operate as a standalone weight controller, offloading the PLC from simple closed-loop control tasks.

User Interface and Diagnostics

The front panel includes a 6-digit red LED display with 7 mm high digits, visible from a distance. Two LED bars show gross/net status and output activation. The three-key membrane keypad allows quick zeroing, taring, or display of min/max values. Diagnostic LEDs indicate power, Ethernet link, and data activity, simplifying on-site troubleshooting.

Industrial Applications

The Laumas TLM8 is widely used in:

• Multi-tank inventory management (chemicals, food, oil)

• Batch mixing and dosing systems

• Conveyor belt scales with multiple weighing zones

• Siloh level monitoring for bulk solids

• Axle weighing and dynamic vehicle scales

Conclusion

The Laumas TLM8 Ethernet TCP/IP weight transmitter is a versatile, high-performance instrument for multi-channel weighing applications. Its robust construction, high-resolution measurement, and open communication protocols make it an excellent choice for integrating weight data into modern PLC-based automation systems.