The advantages of a potentiometer with Modbus RTU

Despite the growing popularity of demand based ventilation systems, which utilizes sensors to determine the ventilation needs, manual ventilation systems are still considered popular. At the design stage of a ventilation system, an important decision is the choice between a simpler manual control via potentiometers or a fully automated control system with sensors that often make manual setting very difficult.

Traditionally, potentiometers, despite their widespread use in almost every ventilation application, were considered as very simple devices with rather limited capabilities. The new SDP-M010 series from Sentera, however, through the use of Modbus RTU, significantly increases the available options regarding ventilation control, both for smaller systems of a single potentiometer – fan pair or for large systems with multiple served rooms and sensors.

The new SDP-M010 potentiometer series, expands the communication capabilities of standard potentiometer through the support of the Modbus RTU communication protocol. The Modbus RTU allows the user to set the potentiometer, read its position and overwrite its output from SenteraWeb or the Building Management System (BMS). These features are additional to the standard features of Sentera’s potentiometers that allow you to set minimum and maximum limits, to set low and high speed through 3 available output options (0-10V, 0-20mA or PWM)

Modbus RTU potentiometers

Sentera's Modbus RTU potentiometers offer numerus additional options that can be set through the Modbus registers:

  • Direction of rotation from minimum to maximum or vice versa
  • Adjustable minimum and maximum output value
  • Output signal type (0-10 VDC, 0-20 mA, 0-100% PWM)
  • Modbus communication timeout
  • Read out potentiometer’s output
  • Overwrite Modbus RTU output

There is a vast range of possible applications of the Modbus RTU potentiometers which include, among others, cases where manual control with remote access and takeover are desired or in cases where a combination of demand based ventilation and manual control is necessary. Examples of such applications include, automatic switch-off outside working hours in offices, free cooling control in commercial buildings or the supply of additional fresh air in rooms during breaks based on sensor measurements.

SDP-M010 series

There are 3 available models of the SDP-M010 series:

  • The SDP-M010-AT with OFF position when completely turned anticlockwise
  • The SDP-M010-BT without OFF position and thus without an output lower than the minimum value set via Modbus
  • The SDP-M010-DC has a dry contact output when completely turned anticlockwise that can turn external equipment on or off