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The EIA once labeled all its standards with the prefix "RS" (Recommended Standard), but the EIA-TIA officially replaced "RS" with "EIA/TIA" to help identify the origin of its standards. Data types are mapped using standard addresses. What is the lifetime of these types of cables? Moreover, RS485 cables are often utilized in systems that require multidrop configurations, where multiple devices share the same communication bus. Rs485 cable is essentially a signal cable with a twisted pair structure, additionally shielded with 2 layers of noise protection used in industrial communication. Anti-inteference layer: Rs485 cables are designed with 2 anti-inteference layers to shield the internal conductors. For fixed laying Maximum shielding capacity in accordance with EMC requirements, Cable for Modbus bus systems, SUCOnet P, Modulink P, VariNet-P, Dry and damp environments, Suitable for various bus systems based on RS485 / RS422. Control and monitoring systems: A single pair of rs485 signal cable can connect up to 32 devices, with a signal transmission distance of up to 1200m. Therefore, using rs485 cables is an ideal choice for industrial control and monitoring systems, especially those with large-scale and high dispersion. Unlike what happens in many energy distribution systems, the manner in which the devices are connected in parallel is important.

Function codes are integer values, ranging from 1 to 255, and the range from 128 to 255 is for exception responses. User-Defined Function Codes are function codes defined by users. They use the digi xtend wireless modems, which are specifically made to be universal, per the manufacturers website (which I take to mean they probably use asynchronous serial communication). This approach helps the cable resist electromagnetic interference and allows extended cable lengths rather than single-ended communication methods. This helps to minimize the impact of electromagnetic interference, causing the voltage between the two wires to deviate. In some countries, inserting two cables into the same screw terminal is permitted. The A signals of all devices should be connected with each other and the same goes for the B signals. These signals are commonly called A and B in RS485 systems. This includes speed control using Variable Frequency Drives (VFD) or inverters, as well as controlling simple PLC and HMI network systems. The transmission speed of RS485 cables can vary depending on factors such as cable length, baud rate, and the quality of the cable itself. Access control systems: Rs485 cables are mainly used to connect and transmit data between access control devices such as security gates, RFID cards, or time attendance machines and the control center.

Server will then read/parse the function code, get the address of the data field of the PDU, then get this data field value and finally perform the action based on the function code. The modem inside the Be1 GSM panel requires a simple GSM SIM card, The Be148 SMS gateway will bidirectionally translate the SMS from the GSM network in MODBUS-RTU commands. Two wire telephone cables will not function because in that case the ground signal levels on both sides will be floating. In order to increase the extent of the Modbus network, repeaters can be used; and signal amplifying and regenerating devices provided with two communication ports that transfer to each what they receive from the other. The maximum number of repeaters that should be serially connected is 3. A higher number introduces excessive delays in the communication system. This ensures maximum protection for the inner core. The maximum number of devices that can be connected to a main cable is 32, including the Master.

In Modbus over Serial Line, the master initiates requests to the slaves in unicast or broadcast modes. A Modbus RS485 connects a Master device to one or more Slave devices. To ensure frame integrity during the transmission, the time interval between two frames must be at least the transmission time of 3.5 characters, and the time interval between two consecutive characters must be no more than the transmission time of 1.5 characters. For example, a value of 122 (7A16) is encoded as two ASCII characters, "7" and "A", and transmitted as two bytes, 55 (3716, ASCII value for "7") and 65 (4116, ASCII value for "A"). Each device has a communication port with two terminals, which are indicated for the sake of convenience as A and B. In these two terminals the communication cable is connected so that all the devices that take part in the communication are connected in parallel.