RMC75S CPU Module

The RMC75S combines multiple communication protocols with RS-232 and RS-485 transceiver options to form a versatile and industrial-hardened communication platform. The RS-232 option provides full-duplex point-to-point communications, while RS-485 allows half-duplex multi-drop networking with up to 128 RMC70s.

Due to limited throughput of serial communications, the RMC75S is best suited for applications where time-critical machine control functions related to motion are implemented in the RMC75S using the User Programs. The serial communications is fine for low-bandwidth monitoring or modifications to the RMC75S parameters or User Programs. In applications where higher throughput is necessary, consider the RMC75E Ethernet module.

Features

One serial RS-232 or RS-485 Communications port
One serial RS-232 Monitor Port
Supported Protocols
- Allen-Bradley DF1 (Full- and Half-duplex)
- Modbus/RTU
- Mitsubishi Bidirectional Protocol

Part Number

The part numbers of the RMC75S is RMC75S. Like all RMC70-series CPU modules, the RMC75S can only be ordered with an axis module.

For example, RMC75S-QA2 is an RMC75S with a two-axis QA2 module.

Specifications

Serial Interface
Transceivers	User-selectable: RS-232, RS-485
Baud Rates	9600, 19200, 38400, 57600, 115200 baud
Stop Bits	1 or 2
Data Length	8 bits
Parity	None, Odd, or Even
Isolation	500 VAC
Electrostatic Discharge (ESD) Protection	15 kV
RS-232 Interface
Type	Single-Ended
Connector	DB-9 Male
Communication Distance	50 ft (12 m)
Network Type	Point-to-Point
RS-485 Interface
Type	Differential
Connector	5-pin Terminal Block
Communication Distance	4000 ft (1200 m)
Network Type	RS-485: Point-to-Point or Multi-drop up to 128 nodes
RS-485 Input Impedance	48 kΩ (1/4 unit load)
Biasing	User selectable
Termination	120 Ω user selectable
RS-232 Monitor Port
Connector	DB-9 Male
Cable	Null modem
Protocol	Allen-Bradley DF1 Full-Duplex, with CRC error detection
Settings	38400 baud, 8 data bits, no parity, 1 stop bit, no handshaking

LEDs

Controller LED

This bi-color (red/green) LED has the following states:

State	Description
Steady Off	No power.
Steady Green	RUN Mode
Flashing Green (Slow)	PROGRAM Mode
Flashing Green (Fast)	Updating Flash or a controller restart is pending.
Flashing Red	The device is in the loader. This should occur briefly when the controller is powered up. If this occurs during normal operation, an error has occurred in the controller and it must be reset. Cycle power to the RMC70 to reset it. Causes: Power Interruption In certain cases, a power interruption to the RMC may cause it to go into the loader. Even a very short interruption, such as 20 msec, can cause problems. This type of interruption cannot be measured with a standard multimeter. For accurate power supply verification, use an oscilloscope or similar high-speed monitoring device. Firmware Bug Certain firmware bugs will cause the RMC to go into the loader. If this occurs, and power interruptions have been ruled out, contact Delta Technical support.
Steady Red	Non-Recoverable major fault. That is, the module cannot boot at all, not even into the loader. The module will likely need to be shipped back to Delta for repair. Some things to try to get it into the Loader (to be done at the direction of technical support) include removing all expansion and axis modules, and setting the Force to Loader jumper under the axis module.

Communication LEDs

These LEDS are located below the Controller LED on a gray background.

Transmit LED
This LED reflects when data is being transmitted on the second serial port (RS-232/485).

State	Description
Steady Off	No power or no data being transmitted.
Steady or Flickering Green	Data is being transmitted.

Receive LED
This LED reflects when data is being received on the second serial port (RS-232/485).

State	Description
Steady Off	No power or no data being received.
Steady or Flickering Green	Data is being received.

Note:
The Monitor Port does not affect any LEDs on the RMC70.