1、When there is no access to the 0 port and the communication port, the power supply will not be damaged if reversed 2、When the power is not connected, the communication port should be able to withstand A-to-ground, B-to-ground, 30V between A and B, and the 485 communication port should not be damaged after 10 seconds 3、When the power is turned on, the voltage of A to ground is 30V, B+ is 30V to ground, and the voltage between A and B is 30V to ground, and cannot be damaged after 10 seconds of pressure 4、Good‑quality engineering plastic material have high mechanical strength, good heat resistance and good electrical insulation 5、RS485 analog extension board come with stable structure, excellent performance and long service life Item Type: RS485 Analog Extension Board Model: WS-ADDAS Material: Engineering Plastic Power Supply Voltage (V): DC8-30 Working Current (mA): 50 ~230 4. Port Description: 4.1 Analog Output Port: 4.1.1 Output Voltage: 0~10V ±5% 4.12 Initial Voltage: 0V 4.2 Analog Input Port: 4.2.1 0'10V Input: A. Impedance 250K B. Withstand voltage -0.7~15V 4.2.2 0'20mA Input: A. Impedance 250Q B. Current: 0'"25mA 4.3 PT100 Temperature Measurement Port: 4.3.1 Divided Into 3 Terminals: A PV, connected to PT100 single-line terminal B.PS, connect one of the compensation lines to c.PG, and connect the other compensation line 4.3.2 After the connection is normal, the correct temperature information can be read 4.3.3 The display temperature when open circuit is about 265 (TVS breakdown) 4.4 K-type Thermocouple Temperature Measurement Port: 4.4.1 Ground can not be connected 4.4.2 Divided into K+ and K- 4.4.3 The open circuit voltage to ground is about 1.3V, and the range of 444 is +-39mV 4.4.5 Short circuit to display the current ambient temperature (equivalent to a thermocouple temperature difference of 0) 4.4.6 The temperature rise can be observed when the thermocouple is connected to the heating 4.4.7 Uncertain output when floating 6. Communication Description: 6.1 In the initial state, the station number is 1, and the baud rate is 04 (9600) 6.2 The parameters can be reset by shorting the TP1 pad on the board, and the reset parameters are in the initial state 6.3 Send HEX to the Expansion Board: 01040000001A71C1 can read the data in the entire buffer (16bit data per register) 6.4 The Returned Data is as Follows: 6.4.1 01 04 34 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 E7 01 14 01 26 01 12 04 60 FF F7 00 24 00 F9 00 01 00 04 10 B8 6.4.2 0~7 are analog output buffer data 6.4.3 8~15 are input data buffer 6.4.4 16~19 are K-type thermocouple temperature data buffer 6.4.5 20~23 are PT100 temperature data buffer 6.4.6 24 is the station number cache 6.4725 is the baud rate parameter buffer 6.5 PT100 Verification: Short-circuit the three PT100 interfaces and input the command "01 06 00 68 11 55 C4 79" to perform PT100 verification, the module will not respond. 6.6 Modify analog output Example: Modify a single analog output Station number/function code/address H/address L/data H/data L/redundancy check code H/redundancy check code L 01 06 00 00 00 00 89 CA Set the first analog output to 0V - data/1000 is the actual output value of the analog Example: Modify multiple analog output Station number/function code/start address H/start address L/quantity H/quantity L/byte number/+++data++++/check H/check L 01 10 00 00 00 02 04 00 10 00 10 F3 A6 Set the first and second analog outputs to 0.016V - bytes=numberx2 1 x RS485 Analog Extension Board 1 x User Manual