EZT-550 Controller Manual
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9. Communications
This section provides information on the communication protocol used to communicate to the EZT-550 over a
serial connection.
CAUTION
Special technical knowledge regarding serial communications is required to utilize the
provided information. Attempted use without understanding all aspects of serial
communications and connections may cause the EZT-550 to perform unexpected
operation, resulting in disorder of the control system, damage, or accidents.
9.1 Connecting a Computer to the EZT-550
9.1.1 RS-232 Serial Connection
To connect the chamber to a computer’s serial port, a null-modem cable is required. This type of cable is
designed to allow two computers to communicate with each other via their serial ports. This cable differs from
that of a standard cable in the fact that the transmit and receive wires are reversed. If one is not available, a
cable can be fashioned rather easily. Use a high quality shielded cable and connect the leads as shown below:
Chamber Serial Connection
Computer Serial Connection
Description Pin
Pin Description
Shield Cover
Cover
Shield
TXD Transmit Data
3
3
TXD Transmit Data
RXD Receive Data
2
2
RXD Receive Data
Signal Ground
5
5
Signal Ground
Connect the cable between the chambers serial port and the desired serial port on the computer. The serial port
settings of the chamber’s serial port are fixed. The computer’s serial port must be set to match the chamber’s
port settings.
Chamber’s Port Settings
Baud Rate:
9600
Data Bits:
7
Stop Bits:
2
Parity:
Even
Device Address: 0
