Product details

• ABB Type Designation:
• CI546
  
• Catalog Description:
• VIP Communication Interface
• Product Net Weight:
• 0.171 kg

1.232-C is a serial physical interface standard developed by the Electronic Industry Association (EIA). RS is the abbreviation of the English "recommended standard", 232 is the identification number, C represents the number of modifications. The RS-232-C bus standard has 25 signal lines, including a main channel and an auxiliary channel, in most cases the main channel is used, for general duplex communication, only a few signal lines can be achieved, such as a sending line, a receiving line and a ground line. The RS-232-C standard specifies that the driver is allowed to have a 2500pF capacitive load, and the communication distance will be limited by this capacitance, for example, when the communication cable is 150pF/m, the maximum communication distance is 15m; If the capacity per meter of cable is reduced, the communication distance can be increased. Another reason for the short transmission distance is that RS-232 is a single-ended signal transmission, there are common ground noise and can not suppress common mode interference and other problems, so it is generally used for communication within 20m.

2.RS-485 bus, when the communication distance is required to be tens of meters to thousands of meters, the RS-485 serial bus standard is widely used. RS-485 uses balanced transmission and differential reception, so it has the ability to suppress common-mode interference. Coupled with the high sensitivity of the bus transceiver, it can detect voltages as low as 200mV, so the transmitted signal can be recovered from kilometers away. RS-485 uses half duplex mode of operation, only one point at any time is in the sending state, so the sending circuit must be controlled by the enable signal. RS-485 is very convenient when used for multi-point interconnection and can eliminate many signal lines. The application RS-485 can be networked to form a distributed system that allows up to 32 drivers and 32 receivers to be connected in parallel.

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