PMA TB45-110-00000-000 rail line TB 45 Temperature Limiter/Monitor

The PMA TB45-110-00000-000 is a DIN-certified temperature limiter and monitor from the rail line TB 45 series, designed for process monitoring applications requiring reliable limit detection and signaling. This compact device provides process value measurement, limit signaling, and switch-off capability, functioning as a Type 2 temperature limiter for safety-critical thermal monitoring. The TB 45 is suitable for heating and refrigeration processes, and can be used as either a temperature limiter, temperature monitor, or general limit indicator where process values other than temperature must be supervised.

Measurement and Input Configuration

The TB45 features one universal input that accepts signals from all common thermocouple types, as well as RTD sensors (PT100) and linear process signals such as 0-10V or 0-20 mA. The universal input flexibility allows one device type to cover many different sensor applications, reducing spare part inventory. The device includes a dual-line LC display for clear indication of measured process value, setpoint values, and configuration parameters. The backlit display ensures readability in various lighting conditions, while additional LED indicators provide status for limit conditions, alarm states, and device operating status. The universal output can be used for repeating the measured value or transmitting a control signal to downstream equipment.

Limit Functions and Operating Modes

The TB 45 can be configured to operate in different modes to suit the specific safety or monitoring requirements of the application. As a temperature limiter, the device responds to exceeding a set limit value by initiating a switching action that typically interrupts the heating circuit or activates an alarm, and requires manual reset after the process value returns to safe levels. As a temperature monitor, the device provides a visual or electrical signal when a limit is exceeded, but does not require manual reset. As a general limit indicator, the TB 45 can monitor any process variable within its input range and provide limit signaling for applications where temperature is not the primary parameter. One limit contact is provided for high-level trip functions, while one pre-alarm contact can be configured to warn operators before the main limit is reached, enabling preventive action before a shutdown condition occurs.

Design and Installation

The TB 45 features a compact construction designed for mounting on standard 35 mm top-hat DIN rail (T-rail), making it suitable for installation inside control cabinets alongside other DIN rail mounted devices. Plug-in screw terminals or spring clamp connectors (depending on model) provide secure field wiring connections that can be removed without disconnecting each individual wire. This pluggable connection design simplifies device replacement for maintenance purposes. The slim design conserves panel space while providing all necessary functions for standalone temperature limit monitoring. The device meets EN 12828 requirements for building heating systems and EN 12953-6 large hot-water boiler applications, as well as DIN 4754 requirements for thermal transfer equipment using organic heat transfer media.

Additional Measurement Capabilities

While the TB 45 is primarily intended as a temperature limiter, its universal input and configurable measurement capabilities allow it to monitor other process parameters including DC current, DC voltage, resistance, and signals from potentiometers. Customer-specific linearization functions are available for non-standard sensors or measurement ranges. Measurement value correction allows calibration against known reference values, compensating for sensor lead resistance or other systematic errors in the measurement chain. Quick response time ensures that limit conditions are detected rapidly, minimizing the risk of process deviations or equipment damage.

Applications and Industry Use

The TB45 is specified for applications where exceeding a defined temperature could cause fire hazards or other dangerous conditions. Typical installations include building heating systems in accordance with DIN EN 12828, large hot-water boilers per DIN EN 12953-6, thermal transfer plants with organic heat transfer media per DIN 4754, and oil-fired installations requiring over-temperature protection. The device may also be used for monitoring drying ovens, heat treatment equipment, chemical reactors, and storage tanks where temperature must be supervised to prevent product degradation or unsafe conditions. The DIN certification verifies device suitability for these safety-critical applications, providing documented evidence for regulatory compliance purposes.

Power Supply and Environmental Conditions

The TB45-110-00000-000 model operates on a power supply voltage of 90-260 V AC, accommodating the common 110V and 220V industrial power standards without requiring voltage selection. This wide-range input capability simplifies ordering and inventory management. Output circuit consists of two relays for alarm and pre-alarm functions, with screw terminal connections. The device is designed for operation in typical industrial environments within the temperature and humidity ranges specified by applicable safety standards.