5.14 Communication5.14.1 RS-485 interface for MODBUSThe device comes equipped with a RS-485 interface for networking via MODBUS. Conntection at: “A(D+)”, “B (D-)” and “GND”.11.03.2014v_am_modbus_connect.vsdID1 GND A(D+)B(D-) ID2GND A(D+)B(D-)B(D-) ID1 GND A(D+)B(D-) ID2GND A(D+)MODBUS(RS-485)MODBUS(RS-485)AddressingAddressingMODBUS(RS-485)MODBUS(RS-485)AddressingAddressingThe connections for MODBUS “A (D+)”, “B (D-)” are available double and are connected with each other internally.Information• You must ensure correct connection; i.e. “A (D+)” must also be connected on the following devicesto “A (D+)”. The same applies to “B (D-)”.• In addition, a "GND" connection must be established, as dissimilar potential (over 10 V!) will lead tothe destruction of the RS-485 interface (e.g. lightning).• Except the data link “A (D+)”, “B (D-)” and “GND” (for automatic addressing additional “ID1” - “ID2”following chapter) no further cable cores of the data line may be used.• Do not use wire shield.• Pay attention to sufficient distance from powerlines and motor wires (min. 20 cm).• A maximum of 64 members can be directly connected to one another, and another 63 members viaa repeater (only for manual addressing i.e. no connection of the terminals “ID1”,“ID2”).Example for MODBUS connectionMODBUS26.02.2007v_modbus_verbindung.vsdThe data line must be conducted from one device to thenext. No other type of wiring is allowed!Always use only two wires of one lead (twisted pair) forthe connection.Recommended wire types1. CAT5 / CAT7 cables2. J-Y (St) 2x2x0.6 (telephone wire)3. AWG22 (2x2 twisted pair)Max allowed wire length 1000 m (CAT5/7 500 m).When using telephone flex with four cable cores, we recommend the following allocation:• A (D+) = red• B (D-) = black• ID1 - ID2 = yellow (for automatic addressing)• GND = whiteDefault interface parameter• Baudrate = 19200• Bits = 8• Parity = Even• Stop bits = 1• Handshake = noneOperating Instructions Fcontrol – model series FXDM25/32AM Electrical installationL-BAL-E212-GB 1451 Index 003 Part.-No.18/123
