主傳輸：BYTES示例/描述從機(jī)11的從機(jī)地址1 0B消息功能代碼1 02讀取數(shù)字輸入狀態(tài)STARTING digital input 2 00 05從數(shù)字輸入5 NUMBER OF DIGITAAL INPUTS 2 00 05 5數(shù)字輸入（即D5、D6、D7、D8、D9）CRC 2 A8 A2 CRC，由主從機(jī)響應(yīng)計(jì)算：BYTES示例/描述從機(jī)11功能代碼1 02讀取繼電器線圈狀態(tài)字節(jié)計(jì)數(shù)1 02 2字節(jié)位掩碼位掩碼2 71請(qǐng)求數(shù)字輸入CRC 2 C5 B9 CRC的01位掩碼，由從機(jī)GE Power Management 469電機(jī)管理繼電器6-7 6通信6.2支持MODBUS功能6示例2：請(qǐng)求從機(jī)11響應(yīng)數(shù)字輸入1至4的狀態(tài)：數(shù)字輸入狀態(tài)D1：訪問關(guān)閉D2：測(cè)試打開D3：啟動(dòng)器狀態(tài)打開D4：緊急重啟打開D5：遠(yuǎn)程重置關(guān)閉D6：可分配輸入1關(guān)閉D7：可指派輸入2關(guān)閉D8：可指定輸入3打開D9：可分派輸入4關(guān)閉位掩碼（LSB）0111 0001主傳輸：BYTES示例/描述從機(jī)11功能代碼1 02的從機(jī)地址1 0B消息讀取數(shù)字輸入狀態(tài)STARTING digital Input 2 00 01從數(shù)字輸入1數(shù)字輸入數(shù)量2 00 04 4數(shù)字輸入（即D1、D2、D3、D4）CRC 2 28 A3由主從機(jī)計(jì)算的CRC響應(yīng)：BYTES示例/描述從機(jī)11功能代碼1 02讀取繼電器線圈狀態(tài)BYTE COUNT 1 01 2字節(jié)位掩碼位掩碼2 01所請(qǐng)求數(shù)字輸入的位掩碼CRC 2 63 90由從機(jī)計(jì)算6-8 469電機(jī)管理繼電器GE Power Management 6.2支持的MODBUS功能6通信6 6.2.3功能代碼03/04：讀取設(shè)定值/實(shí)際值MODBUS實(shí)現(xiàn)：讀取輸入和保持寄存器469實(shí)現(xiàn)：讀取設(shè)定點(diǎn)和實(shí)際值對(duì)于MODBUS的469實(shí)現(xiàn)，這些命令可用于讀取任何設(shè)定值（“保持寄存器”）或?qū)嶋H值（“輸入寄存器”）。保持寄存器和輸入寄存器是16位（兩字節(jié)）值，先以高位字節(jié)傳輸。因此，所有469個(gè)設(shè)定值和實(shí)際值都作為兩個(gè)字節(jié)發(fā)送。一次傳輸中可讀取的最大寄存器數(shù)為125。功能代碼03和04被配置為可互換地讀取設(shè)定值或?qū)嶋H值，因?yàn)槟承㏄LC不支持這兩個(gè)功能代碼。從機(jī)對(duì)這些功能碼的響應(yīng)是從機(jī)地址、功能碼、后續(xù)數(shù)據(jù)字節(jié)數(shù)的計(jì)數(shù)、數(shù)據(jù)本身和CRC。每個(gè)數(shù)據(jù)項(xiàng)都以兩字節(jié)的形式發(fā)送，首先發(fā)送高階字節(jié)。CRC以兩字節(jié)數(shù)的形式發(fā)送，低位字節(jié)先發(fā)送。消息格式和示例請(qǐng)求從機(jī)11以地址0308開始的2個(gè)寄存器進(jìn)行響應(yīng)。在本例中，這些地址中的寄存器數(shù)據(jù)為：地址數(shù)據(jù)0308 0064 0309 000A主傳輸：BYTES示例/描述從站地址1 0B消息從站11功能代碼1 03讀取寄存器數(shù)據(jù)起始地址2 03 08數(shù)據(jù)起始于0308設(shè)置點(diǎn)數(shù)量2 00 02 2個(gè)寄存器（共4字節(jié)）CRC 2 45 27 CRC，由主從站響應(yīng)計(jì)算：BYTES示例/描述從機(jī)11的從機(jī)地址1 0B響應(yīng)消息功能代碼1 03讀取寄存器字節(jié)計(jì)數(shù)1 04 2寄存器=地址0308中的4字節(jié)數(shù)據(jù)1 2 00 64值數(shù)據(jù)2 2 00 0A地址0309中的值CRC 2 EB 91 CRC由從機(jī)GE Power Management 469電機(jī)管理繼電器6-9 6通信6.2支持的MODBUS功能6 6.2.4功能代碼05：執(zhí)行操作MODBUS實(shí)施：強(qiáng)制單線圈469實(shí)施：執(zhí)行操作此功能代碼允許主機(jī)請(qǐng)求469執(zhí)行特定命令操作。

MASTER TRANSMISSION: BYTES EXAMPLE / DESCRIPTION SLAVE ADDRESS 1 0B message for slave 11 FUNCTION CODE 1 02 read digital input status STARTING DIGITAL INPUT 2 00 05 starting at digital input 5 NUMBER OF DIGITAL INPUTS 2 00 05 5 digital inputs (i.e. D5, D6, D7, D8, D9) CRC 2 A8 A2 CRC calculated by the master SLAVE RESPONSE: BYTES EXAMPLE / DESCRIPTION SLAVE ADDRESS 1 0B response message from slave 11 FUNCTION CODE 1 02 read relay coil status BYTE COUNT 1 02 2 byte bit mask BIT MASK 2 71 01 bit mask of requested digital input CRC 2 C5 B9 CRC calculated by the slave GE Power Management 469 Motor Management Relay 6-7 6 COMMUNICATIONS 6.2 SUPPORTED MODBUS FUNCTIONS 6 Example 2: Request slave 11 to respond with status of digital inputs 1 to 4: Digital Input Status D1: Access Closed D2: Test Open D3: Starter Status Open D4: Emergency Restart Open D5: Remote Reset Closed D6: Assignable Input 1 Closed D7: Assignable Input 2 Closed D8: Assignable Input 3 Open D9: Assignable Input 4 Closed Bit Mask (LSB) 0111 0001 MASTER TRANSMISSION: BYTES EXAMPLE / DESCRIPTION SLAVE ADDRESS 1 0B message for slave 11 FUNCTION CODE 1 02 read digital input status STARTING DIGITAL INPUT 2 00 01 starting at digital input 1 NUMBER OF DIGITAL INPUTS 2 00 04 4 digital inputs (i.e. D1, D2, D3, D4) CRC 2 28 A3 CRC calculated by the master SLAVE RESPONSE: BYTES EXAMPLE / DESCRIPTION SLAVE ADDRESS 1 0B response message from slave 11 FUNCTION CODE 1 02 read relay coil status BYTE COUNT 1 01 2 byte bit mask BIT MASK 2 01 bit mask of requested digital input CRC 2 63 90 CRC calculated by the slave 6-8 469 Motor Management Relay GE Power Management 6.2 SUPPORTED MODBUS FUNCTIONS 6 COMMUNICATIONS 6 6.2.3 FUNCTION CODES 03/04: READ SETPOINTS/ACTUAL VALUES Modbus implementation: Read Input and Holding Registers 469 Implementation: Read Setpoints and Actual Values For the 469 implementation of Modbus, these commands can be used to read any Setpoint ("holding registers") or Actual Value ("input registers"). Holding and input registers are 16 bit (two byte) values transmitted high order byte first. Thus all 469 Setpoints and Actual Values are sent as two bytes. The maximum number of registers that can be read in one transmission is 125. Function codes 03 and 04 are configured to read setpoints or actual values interchangeably because some PLCs do not support both function codes. The slave response to these function codes is the slave address, function code, a count of the number of data bytes to follow, the data itself and the CRC. Each data item is sent as a two byte number with the high order byte sent first. The CRC is sent as a two byte number with the low order byte sent first. MESSAGE FORMAT AND EXAMPLE Request slave 11 to respond with 2 registers starting at address 0308. For this example the register data in these addresses is: Address Data 0308 0064 0309 000A MASTER TRANSMISSION: BYTES EXAMPLE / DESCRIPTION SLAVE ADDRESS 1 0B message for slave 11 FUNCTION CODE 1 03 read registers DATA STARTING ADDRESS 2 03 08 data starting at 0308 NUMBER OF SETPOINTS 2 00 02 2 registers (4 bytes total) CRC 2 45 27 CRC calculated by the master SLAVE RESPONSE: BYTES EXAMPLE / DESCRIPTION SLAVE ADDRESS 1 0B response message from slave 11 FUNCTION CODE 1 03 read registers BYTE COUNT 1 04 2 registers = 4 bytes DATA 1 2 00 64 value in address 0308 DATA 2 2 00 0A value in address 0309 CRC 2 EB 91 CRC calculated by the slave GE Power Management 469 Motor Management Relay 6-9 6 COMMUNICATIONS 6.2 SUPPORTED MODBUS FUNCTIONS 6 6.2.4 FUNCTION CODE 05: EXECUTE OPERATION Modbus Implementation: Force Single Coil 469 Implementation: Execute Operation This function code allows the master to request an 469 to perform specific command operations.