RS485 control module RBT40

Product information
The robutec RBT40 analog module provides manual override and control of four analog outputs located on a DDC or connected fieldbus devices. It includes four rotary encoders with integrated push‑buttons; each encoder is paired with a 10‑segment LED bargraph and an individual status LED. Bargraphs support dimming of the last illuminated segment to indicate intermediate values. Analog setpoints are queried via Modbus and made available to the DDC for controlling analog points such as valves or dampers. Status LEDs are controlled via Modbus commands while the bargraphs reflect values set with the rotary encoders. Brightness of the bargraphs can be adjusted for the entire module via a configuration register. A lamp test can be triggered locally (test button) or via Modbus. Registers are provided to read button presses and changed analog values; reading these registers clears the corresponding bits. For system configuration (addressing, maximum modules per Modbus master, mounting, bus connection, etc.) refer to the configuration chapter.

Functions / features

• Manual override and control of 4 analog outputs
• 4 rotary encoders with integrated push‑buttons
• Each encoder: 10‑segment LED bargraph + separate status LED
• Dimming of last segment for higher visual resolution (intermediate values)
• Communication and querying of analog values via Modbus
• Status LEDs controllable via Modbus commands
• Bargraph brightness adjustable via configuration register
• Lamp test triggerable locally (button) or via Modbus
• Registers available to query button presses and changed analog values; reading resets bits

Technical specifications

• Manufacturer: romutec Steuer- und Regelsysteme GmbH
• Model: RBT40
• Product number / SKU: 00003003
• Weight: 0.097 kg
• Supply voltage: 24 V DC (±10%)
• Current consumption: max. 150 mA (all bargraphs full scale)
• Bus interface: RS485
• Protocol: Modbus RTU (8 N 1)
• Supported baud rates: 9,600 / 19,200 / 38,400 / 57,600
• Analog outputs (on DDC / fieldbus device): 4 (manually overrideable via encoders)
• Controls: 4x rotary encoder with integrated push‑button
• Displays: 4x 10‑segment LED bargraphs + 4x individual LEDs; dimmable last segment
• EEPROM write cycles: up to 100,000
• Operating temperature: 0…50 °C
• Storage/transport temperature: 0…70 °C
• Relative humidity: 10…90% (non‑condensing)
• Protection class: IP20

Integration / Installation
Connect the module to the central terminal via the flat ribbon cable. Wire RS485 according to the system documentation and configure Modbus addressing as described in the configuration chapter. Observe the maximum number of modules per Modbus master and follow mounting and bus connection guidelines in the manual for reliable operation.