Because a mark (logic 1) condition is traditionally represented (e.g. in RS-232) with a negative voltage and space (logic 0) represented with a positive one, A may be considered the non-inverting signal and B as inverting. With Modbus, BACnet and Profibus, A/B labeling refers A as the negative green wire and B as the positive red wire, in the definition of the D-sub connector and M12 circular connector, as can be seen in Profibus guides. However this contradicts the facts that an idle mark state is a logical one and the termination polarization puts B at a higher voltage in Profibus guidelines. RS-485 is used as the physical layer underlying many standard and proprietary automation protocols used to implement industrial control systems, including the most common versions of Modbus and Profibus. RS-485 is also used in building automation as the simple bus wiring and long cable length is ideal for joining remote devices. RS-485 is used for low-speed data communications in commercial aircraft cabins' vehicle bus. This allows RS-485 to implement linear bus topologies using only two wires.

Care must be taken when using A/B naming. The end resistance must be used only at the ends of the main cable. Without termination resistors, signal reflections off the unterminated end of the cable can cause data corruption. Electric noise can cause all kinds of problems for electronics. This allowed for electrical noise to cause interference. Termination resistors also reduce electrical noise sensitivity due to the lower impedance. Another plus for RS485 is that it is less susceptible to noise issues. The greatest feature of RS485 is the fact that you can connect up to 32 devices on one system. If there are several sensors near and/or other data to be transmitted via GSM, it is more convenient to use Standard / RF versions supported on a concentrator or controller such as RXTXeasy GSM so you will be able to use one single SIM. There is also the GSM version; especially useful when only one sensor is needed in a remote location where other types of transmission cannot be used. GSM 58,90 EUR Sonda Umidità addiz. 2) the GSM version also allows you to indicate a possible PIN (leave blank if there is no PIN) and the operator's APN (possibly you can search for it on Google).

There is no standard connector for the protocol. RS-485 does not specify any connector or pinout. RS-422 and RS-485 Standards Overview and System Configurations, Application Report (pdf). Texas Instruments (Technical report). A (green, negative) is higher than B (red, positive). If A is negative with respect to B, the state is binary 1. The reversed polarity (A positive with respect to B) is binary 0. The standard does not assign any logic function to the two states. This section also defines the logic states 1 (off) and 0 (on), by the polarity between A and B terminals. Section 4 defines the electrical characteristics of the generator (transmitter or driver), receiver, transceiver, and system. RS-485, also known as TIA-485(-A) or EIA-485, is a standard, originally introduced in 1983, defining the electrical characteristics of drivers and receivers for use in serial communications systems. These characteristics make RS-485 useful in industrial control systems and similar applications. Electrical signaling is balanced, and multipoint systems are supported. RS-485 signals are used in a wide range of computer and automation systems. We have also included the most widespread industrial standards, HTTP and MQTT, so that our elements can be used in any automation.

It is interesting to measure the humidity of the ground, but we have also thought about other things; and then we have TXtemp to measure the temperature (one of the uses of TXtemp is in association with SuperClock), and for practically any type of measurement we have TXdata (RS232, RS485 ModBus) - which can be connected to thousands of existing third-party professional RS232 or ModBus meters (and there is something for all needs: temperature and humidity meters, anemometers, voltage meters, energy, light meters, water meters, presence sensors, brightness sensors, soil humidity sensors, etc. ; practically all professional meters are available in ModBus or RS232 standard; and not just meters). There is a slight surcharge which covers PayPal fees. It has a special capacitive sensor designed by us, efficient and of good precision, waterproof, rs485 cable resistant to oxidation and not subject to variations due to salinity and soil composition: better than this there are only the "extraction pressure" sensors (which we do not propose because they are not durable and also the sensor alone costs hundreds of euros). TXsoil is a compact and low consumption sensor that can measure and transmit the humidity of the ground WiFi or RF or GSM. We tried to build an organic system so that whoever gets a TXtemp, TXsoil sensor or a bridge for RS232 or ModBus sensors and devices like TXdata can immediately use them without wasting time in configurations (and we also took the opportunity to insert some things into our system some "extra" not foreseen by the standards!).