Danfoss FC 102 Design Manual

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Contents

NOTICECoils and registers are addressed explicitly with an off-set of -1 in Modbus.I.e. Coil 33 is addressed as Coil 32.8.10.2 Force/Write Single Coil (05 HEX)DescriptionThis function forces the coil to either ON or OFF. Whenbroadcast, the function forces the same coil references inall attached followers.QueryThe query message specifies the coil 65 (parameter writecontrol) to be forced. Coil addresses start at zero, that is,coil 65 is addressed as 64. Force Data=00 00HEX (OFF) orFF 00HEX (ON).Field Name Example (HEX)Follower Address 01 (Frequency converter address)Function 05 (write single coil)Coil Address HI 00Coil Address LO 40 (64 decimal) Coil 65Force Data HI FFForce Data LO 00 (FF 00=ON)Error Check (CRC) -Table 8.23 QueryResponseThe normal response is an echo of the query, returnedafter the coil state has been forced.Field Name Example (HEX)Follower Address 01Function 05Force Data HI FFForce Data LO 00Quantity of Coils HI 00Quantity of Coils LO 01Error Check (CRC) -Table 8.24 Response8.10.3 Force/Write Multiple Coils (0F HEX)DescriptionThis function forces each coil in a sequence of coils toeither ON or OFF. When broadcasting the function forcesthe same coil references in all attached followers.QueryThe query message specifies the coils 17 to 32 (speed set-point) to be forced.Field Name Example (HEX)Follower Address 01 (frequency converter address)Function 0F (write multiple coils)Coil Address HI 00Coil Address LO 10 (coil address 17)Quantity of Coils HI 00Quantity of Coils LO 10 (16 coils)Byte Count 02Force Data HI(Coils 8-1)20Force Data LO(Coils 16-9)00 (ref.=2000 hex)Error Check (CRC) -Table 8.25 QueryResponseThe normal response returns the follower address, functioncode, starting address, and quantity of coils forced.Field Name Example (HEX)Follower Address 01 (frequency converter address)Function 0F (write multiple coils)Coil Address HI 00Coil Address LO 10 (coil address 17)Quantity of Coils HI 00Quantity of Coils LO 10 (16 coils)Error Check (CRC) -Table 8.26 Response8.10.4 Read Holding Registers (03 HEX)DescriptionThis function reads the contents of holding registers in thefollowing.QueryThe query message specifies the starting register andquantity of registers to be read. Register addresses start atzero, i.e. registers 1-4 are addressed as 0-3.Field Name Example (HEX)Slave Address 01Function 03 (read holding registers)Starting Address HI 0B (Register address 3029)Starting Address LO D5 (Register address 3029)No. of Points HI 00No. of Points LO 02 - (Par. 3-03 is 32 bits long, i.e.2 registers)Error Check (CRC) -Table 8.27 Example: Read 3-03 Maximum Reference, register 03030Installation and Set-up Design Guide142 Danfoss A/S © Rev. 06/2014 All rights reserved. MG11BC0288