Or a Control Bus that has a number of manufacturers backing the standard. Finally there is confusion from the IC manufacturers. Figure 2. Mechanical Layout of the SS4544 System Indicators There are nine indicators on the system, electronic axis fuses, power, brake, and communications status. Brake (6) - This red LED is lit whenever power is being absorbed by the system due to dynamic braking, i.e. the motors are acting as generators during deceleration. RS-232-out (8) - This green LED is lit whenever the data output is in the true state. RS-232-in (7) - This green LED is lit whenever the data input is in the true state. RS485 (9) - This green LED is lit whenever data on the RS485 bus is active. Power (5) - This green LED is lit whenever system power is running. This allows a complete turnkey system to be implemented within the unit. The standard power converter uses an auto switcher to convert to an internal 240-400VDC raw supply which is then converted with an isolated flyback switching regulator to the internal system voltages. The switching regulator is synchronized with the motor drive chop rate to eliminate noise coupling. These characteristics make it well-suited for operation in noisy electrical environments and various applications, including industrial automation, e-metering, and motor control.

If this is required, it can be accomplished by any means desired including RS-485 drivers on an additional network, RS-232 drivers on extra wires, TTL levels, or really anything you can dream up since it won't work with any other RS-485 network except the one you are designing. Various build options are possible including 4-wire serial, 1x10-pin female ComBoard header, RS485 standard or a 2x5-pin shrouded header for use with ribbon cables. The PCB-CB485 is a bare PCB to build the CB485 logic-level to RS-485 adapter. Build with 1x10 male header for use with solderless breadboards. With the 1x10 male header option, the CB485 can be used with solderless breadboards. The CB485 can be used with a wide number of RS-485 converter ICs using the common MAX483 and MAX485 half-duplex 8-pin DIP pinout. Drivers with this pinout are available from Texas Instruments, Analog Devices, Linear Technologies, Exar, Maxim and others. The RS-485 standard requires a minimum performance, but many drivers exceed this performance and some have quirks such as slew rate limiting.

Other reasons that some RS-232 ports were half-duplex: some very old UARTs may be half-duplex limiting the system, and some very old computers drove the RS-232 drivers directly from the processor without a UART. Care must be taken that an SC connection, especially over long cable runs, does not result in an attempt to connect disparate grounds together - it is wise to add some current limiting to the SC connection. Motors (A,B,C,D) - These are standard 5 pin Combicon 0.2" pin spacing connectors, which are used for the step motor connections. They mate to a standard screw terminal connector for easy connection to motor leads. Motors are driven bi-polar so only 4 leads are necessary, plus a fifth which is grounded for noise shielding. The connectors latch to prevent accidental extraction. Limits (E,F,G,H) - These are standard 6 pin Molex 0.1" Tripeg connectors. A user slot and connection to the processor and power is available for custom interfaces that cannot be handled by the standard hardware set. H1 is a IEC 61158 standard, and ANSI standard. Uses IEC/ISA-S50.02-1992 as the standard, as does Profibus.

The CB485 uses the ComBoard standard for interchangeable serial interface modules. The original "RS-232 compatible" serial port used a UART to drive the RS-232 electrical signal levels and many came to believe that the UART protocol was a part of the RS-232 standard. An unterminated network may improve signal quality where a star bus topology has to be used. SC, G or reference, the common signal reference ground used by the receiver to measure the A and B voltages. There is no wire shown connecting this third point between driver and receiver. The provided diagram illustrates the equivalent output schematic of the RS485 driver. The BOM (bill of materials) and schematic diagram are available below to construct the circuit. The Physical Layer, Data Link Layer, and Application Layer are specified. Low capacitance cable becomes important when pushing line length and/or data rates to the maximum. Its annex also states "It is desirable for proper operation over the interchange cable that the DC wire resistance not exceed 25 Ω per conductor." Any cable that meets the capacitance requirement can be used. Add the cost of pulling the cable and long networks can get very expensive. If you can get within 10%, you can expect it to work.