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What is RS485 biasing?
With RS485 networks, there are periods of time when no driver is actively driving the bus. Fail-safe bus biasing is one way to alleviate this problem. The objective of biasing is to make sure that the RS485 line remains in a known, non-fluctuating state when no devices are transmitting.
What is common mode voltage in RS485?
The common-mode voltage range for RS-485 is expanded to −7 V to +12 V. The RS-485 transceivers must withstand this common-mode voltage range while tristated (disconnected from the bus). An RS-485 system must have a driver that can be disconnected from the transmission line when a particular node is not transmitting.
How far can RS485 be run?
4,000 feet
RS485 is popular for inexpensive local networks, multidrop communication links and long haul data transfer over distances of up to 4,000 feet. The use of a balanced line means RS485 has excellent noise rejection and is ideal for industrial and commercial applications.
When was RS-485 invented?
1998
RS-485 has been used in a wide range of computer automation systems dating back to when the standard was created in 1998.
When to use bias and termination in RS-485?
Biasing and termination are used to make an RS-485 network more robust and communication more reliable in certain RS-485 network designs. If you’re having communication problems on your network, termination and biasing are usually the first place to start in improving RS-485 network communication.
Are there any low power RS-485 transceivers in the market?
Active in Production. The MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and one receiver. Click any title below to view the detail page where available.
What are the strengths of the RS-485 cable?
RS-485 has a lot of strengths. With an RS-485 connection you can run a cable thousands of feet and successfully transmit data across the line, be it a short or long RS-485 line.
How many devices are allowed on a RS-485 network?
On RS-485 networks only one device is allowed to communicate at a time; otherwise data collisions may occur. In master/slave protocols this is less of a concern, because the master is usually initiating requests and then slaves respond at that time.