ABB ACH550-UH User Manual

Also see for ACH550-UH HVAC: User manual Installation, operation & maintenance manual User manual User manual User manual

Contents

ABB ACH550-UH User Manual Manual pdf 155 page image

ACH550-UH User’s Manual 155Embedded FieldbusMechanical and Electrical Installation – EFBWarning! Connections should be made only while the drive is disconnectedfrom the power source.Drive terminals 28 …32 are for RS485 communications.• Use Belden 9842 or equivalent. Belden 9842 is a dual twisted, shielded pair cablewith a wave impedance of 120 Ω.• Use one of these twisted shielded pairs for the RS485 link. Use this pair toconnect all A (-) terminals together and all B (+) terminals together.• Use one of the wires in the other pair for the logical ground (terminal 31), leavingone wire unused.• Do not directly ground the RS485 network at any point. Ground all devices on thenetwork using their corresponding earthing terminals.• As always, the grounding wires should not form any closed loops, and all thedevices should be earthed to a common ground.• Connect the RS485 link in a daisy-chained bus, without dropout lines.• To reduce noise on the network, terminate the RS485 network using 120 Ωresistors at both ends of the network. Use the DIP switch to connect or disconnectthe termination resistors. See following diagram and table.• Connect the shield at each end of the cable to a drive. On one end, connect theshield to terminal 28, and on the other end connect to terminal 32. Do not connectthe incoming and outgoing cable shields to the same terminals, as that wouldmake the shielding continuous.• For configuration information see the following:– "Communication Set-up – EFB" below.– "Activate Drive Control Functions – EFB" on page 159.– The appropriate EFB protocol specific technical data. For example, "ModbusProtocol Technical Data" on page 169.X1 Identification Hardware Description28 Screen29 B (Positive +)30 A (Negative -)31 AGND32 ScreenTerminated TerminatedStation Station Station Station28 SCR29 B30 A31 AGND32 SCRSCR+-GNDRS485 Multidrop application RS485 interfaceBus terminationOFF position ON positionSCR+-GNDJ2ONJ2ON