INFICON MDC-370 Thin Film Deposition Controller - Manual (Page 132)

MDC-370 DEPOSITION CONTROLLER
lists pin signal assignments, including a definition of whether the signal is an
output from the MDC-370 or an input to the MDC-370.
The DJ11 jack located on the front panel and labeled RS-232 cannot be used if
RS-485 is installed.
The MDC-370’s RS-485 port is automatically set up to operate with the following
specifications:
9600 Baud, 8 Bit data, No Parity, 1 Stop bit
11.4 IEEE-488 PARALLEL INTERFACE
The optional IEEE-488 interface provides the MDC-370 with the ability to
communicate with computers and other devices over a standard IEEE-488
interface bus. The IEEE-488 interface, also known as GPIB or HPIB, provides an
eight bit parallel asynchronous interface between up to 15 individual devices on
the same bus. This means that one computer equipped with an IEEE-488
interface card can communicate with up to 14 MDC-370 controllers or other
devices.
The pin layout of the IEEE-488 port is shown in Figure 8-5 and Table 8-3 lists
pin signal assignments, including a definition of whether the signal is an output
from the MDC-370 or an input to the MDC-370.
Both of the RS-232 serial ports can still be used with IEEE-488 installed.
However, since both interfaces use the same input and output message buffers,
they should not be used at the same time. This will result in communication
errors.
11.5 PROTOCOL
All communications between the computer and the MDC-370 are in the form of
message character strings with the format:
* Two byte header - FFh,FEh i.e. Chr$(255),Chr$(254)
*One byte controller address - The controller address byte defines the controller
that should receive the message, or should respond to the message by transmitting
data. The controller address will range from 0 to 32 (set via Edit System Setup,
Edit Utility Setup, Interface Address). A controller address of zero will be
received by all controllers except in the case of the IEEE-488 interface. With this
interface, only the addressed device will receive the message.
*One byte instruction code.
*One byte message length.
* 0-249 byte message.
* One byte checksum, for the instruction code byte, message length byte and the
0-249 byte message.
COMPUTER INTERFACE 11-2