From the computer to the controller, there are multiple options, and since the controller is usually within sight of the computer, there is no need to reinvent the wheel, so to speak, on that. Now there was certain instances I used STP wire for rs485 because I had a lot of devices connected in a long run chain (DMX512 lighting fixtures). It seems if there is a lot of RFI in the installation, shielded twisted cable can be justified. No, There may be interference from the high voltages and currents present on the mains wires, and if there is any insulation fault, arcing, etc. on the mains wires, it could put dangerous voltages on the low-voltage RS485 network cable. Star and ring topologies are not recommended because of signal reflections or excessively low or high termination impedance. 5 should work in your situation because of the voltage you will be running (5-10V) and your signal is not high frequency (above 500Mhz) in the first place. 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.

It consists of two insulated copper conductors twisted together, which helps reduce electromagnetic interference and ensures signal integrity. I’m wanting to use the photon/electron for an rs485 cable replacement between two pieces of equipment, no computer on either end. Converters between RS-485 and RS-232 are available to allow a personal computer to communicate with remote devices. We need to test the operation of a computer Belden cable RS485 for one of our clients. If you are planning to replace the cable between two existing RS485 nodes, you need a way to talk to the nodes on either side, and that would still be RS485. What are the two end-nodes? AI Devices) are only stating the "transport" but don’t really provide any detail about the protocol. DH 485 is a proprietary communications protocol used by Allen-Bradley in their line of industrial control units. Refurbished units will be of equivalent functionality and performance to a new unit and will have undergone rigorous testing to ensure compliance with warranty standards. 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.

Can you tell me what kind of test can we perform in order to determine if this cable needs to be replaced or is already working fine? But any twisted pair cable with overall screen should be fine. In addition to the serpentine pair configuration, STP cables feature a metallic shield surrounding the conductors. It gets away most of the time with this configuration, with the shield draining noise and providing the ground reference at the same time. 5-pair configuration, although less common, may refer to a special configuration where additional pairs are used for signaling or other purposes, enhancing the reliability. The WattNode® BACnet and Modbus® meters communicate using RS-485 (TIA/EIA-485-A) half-duplex, differential signaling at 9600, 19200, 38400, and 76,800 baud. TSB-89A, Application Guidelines for TIA/EIA-485-A does not recommend using star topology. The foreword to the standard references The Telecommunications Systems Bulletin TSB-89 which contains application guidelines, including data signaling rate vs. Electrical signaling is balanced, and multipoint systems are supported. RS-485 supports inexpensive local networks and multidrop communications links, using the same differential signaling over twisted pair as RS-422. The twisted pair design allows RS-485 to achieve better noise immunity, making it suitable for environments with electrical interference.

Be sure to use a wire pair such as the blue and blue/white pair for the data lines and a third wire or pair twisted together for the common connection. The shielding minimizes the risk of signal degradation, making STP cables suitable for applications where data integrity is crucial. As a rule of thumb, the speed in bit/s multiplied by the length in metres should not exceed 108. Thus a 50-meter cable should not signal faster than 2 Mbit/s. Yes, it would work for that too, but 24 awg cable with plenum grade jacket is the standard. Furthermore, there are plenum-rated RS-485 cables designed for use in building plenum spaces. In practice, Cat 5 cables have been used successfully in many installations, but there are some concerns. The capacitance is close to 12.5 pF/foot but there is a small impedance mismatch (100 ohms for Cat 5, 120 ohms for RS-485). End of line termination resistor (120 ohm 1/4 watt) to be installed at both ends of network. The value of each termination resistor should be equal to the cable characteristic impedance (typically, 120 ohms for twisted pairs). The cable recommended in this type of connection is the Belden 9842, which has 2 twisted pairs.