2716 RS-232 Communications Module
The
model 2716 Communications Module adds two RS-232 ports to Control Tech's
automation controllers. These ports are optoisolated from the controller's logic
circuitry, as well as the I/O power system for the controller, providing
protection in instances where serial devices are located in electrically harsh
environments. This can be important when connecting devices such as computers,
operator interface terminals, barcode readers, motor drives, and other devices
subject to electrostatic discharge and noise generation.
The model 2716 supports the full protocol suite of the controller in which it
resides. As with the controller's on-board port, any of the controller's
internal registers, flags, and other resources may be monitored or changed.
Programming can be accomplished via either serial port, and outbound message
transmitting is also possible.
A Flexible Hardware Architecture
The two serial ports on the model 2716, terminating in modular jacks on the
module's front panel, may be software-configured to one of six baud rates from
1200 baud to 38.4k baud.
Special purpose registers can be used to read individual characters in either
port's input buffer, or to automatically parse an ASCII numeric value out of a
response from an external device. This latter feature is useful when obtaining
readings from external scales or other transducers that return a value in the
form of an ASCII string.
An additional RS-485 port is present on the front panel. This port can be
jumper-configured to replace one of the RS-232 ports, providing longer distance
communications via a balanced differential circuit.
Local CPU for Data Handling
The model 2716 is equipped with a 32-bit processor, allowing operation of
both ports at full rated speed without encumbering the controller's CPU.
Complete messages are assembled locally on the module, and only then are passed
to the controller's processor for servicing.
