Introduction

Introduction 1:
EL6861

1-channel BACnet MS/TP interface RS485, D-sub connection

The EL6861 serial interface enables the connection of BACnet MS/TP devices (Master-Slave/Token-Passing) via an RS485 interface. Up to 32 MS/TP devices (up to 64 if ultra-low power transceivers are used) can be connected. Use the EL6861 interface only in combination with TwinCAT and CX9020 as a minimum, since the BACnet MS/TP driver integrated in TwinCAT implements the communication via the MS/TP protocol (BACnet revision 12). The configuration is also done in TwinCAT.

The RS485 interface guarantees high interference immunity through electrically isolated signals. The EL6861 provides 1 x 5 V DC at 20 mA (electrically isolated, short-circuit proof) from the E-bus supply for use with the bias resistors (network bias).

The following devices are typically connected to the EL6861:

  • Frequency converters
  • Pumps
  • Drives (especially valve drives)
  • Room control units
  • Compact controllers (e.g. volume flow regulators)