Lake Shore Model 340 Temperature Controller User’s Manual
Remote Operation
9-13
9.2 SERIAL INTERFACE OVERVIEW
The serial interface used in the Model 340 is commonly referred to as an RS-232C interface. RS-232C is a
standard of the Electronics Industries Association (EIA) that describes one of the most common interfaces
between computers and electronic equipment. The RS-232C standard is quite flexible and allows many
different configurations. However, any two devices claiming RS-232C compatibility cannot necessarily be
plugged together without interface setup. The remainder of this paragraph briefly describes the key features
of a serial interface that are supported by the instrument. A customer supplied computer with similarly
configured interface port is required to enable communication.
9.2.1 Changing Baud Rate
If using the Serial Interface, the user must set the Terminator, BPS, and Parity. Press the
Interface
key to
display the
COMPUTER INTERFACE
screen. The user has the option to change the Baud rate, Parity, and
Terminator. Refer to Table 9-4. Use the
s
or
t
key make selections. Use the
Next Setting
key to advance to
the next parameter. Finally, use the
Save Screen
key to accept the changes or the
Cancel Screen
key to
decline the changes.
9.2.2 Physical
Connection
The Model 340 has an RJ-11 connector on the rear panel for serial communication. The original RS-232C
standard specifies 25 pins, but 9-pin, 25-pin, and RJ-11 connectors are commonly used in the computer
industry. For you convenience, Lake Shore offers a Model 2001 RJ-11 Cable. When combined with either the
Model 2002 DB-25 Adapter or Model 2003 DE-9 Adapter, this cable assembly can be used to connect the
instrument to a computer with the corresponding connector type. See Figure 9-4. These adapters are
described in Paragraph 10.2 and are schematically diagramed in Figures 11-8 thru 11-10.
Equipment with Data Communications Equipment (DCE) wiring can be connected to the instrument with a
straight through cable. However, if the interface is for Data Terminal Equipment (DTE), a Null Modem Adapter
is required to exchange the transmit (TxD) and receive (RxD) lines.
The instrument uses drivers to generate the transmission voltage levels required by the RS-232C standard.
These voltages are considered safe under normal operating conditions because of their relatively low voltage
and current limits. The drivers are designed to work with cables up to 50 feet in length.
SERIAL I/O
LSCI Model
2002 RJ-11
to DB-25
Adapter
LSCI Model 2003 RJ-11
to DE-9 Adapter
LSCI Model 2001 RJ-11
Cable Assembly
Serial Interface
Output on rear of
Model 340
The Model 2001 and 2003 are
included with the Model 340.
The Model 2002 is an option
available from Lake Shore. .
To customer-supplied
computer with DB-25
Serial Interface
Connector configured
as DCE. If the
interface is DTE, a
Null Modem Adapter
is required to
exchange Transmit
and Receive lines.
To customer-supplied
computer with DE-9
Serial Interface
Connector configured
as DTE. If the interface
is DCE, a Null Modem
Adapter is required to
exchange Transmit and
Receive lines.
1
340-9-2.CVS
Figure 9-4. Serial Interface Connections