Lake Shore Model 331 Temperature Controller User’s Manual
6.2.5 Message
Flow
Control
It is important to remember that the user program is in charge of the serial communication at all times.
The instrument can not initiate communication, determine which device should be transmitting at a
given time or guarantee timing between messages. All of this is the responsibility of the user program.
When issuing commands only the user program should:
•
Properly format and transmit the command including terminators as one string.
•
Guarantee that no other communication is started for 50 ms after the last character is transmitted.
•
Not initiate communication more than 20 times per second.
When issuing queries or queries and commands together the user program should:
•
Properly format and transmit the query including terminators as one string.
•
Prepare to receive a response immediately.
•
Receive the entire response from the instrument including the terminators.
•
Guarantee that no other communication is started during the response or for 50 ms after
it completes.
•
Not initiate communication more than 20 times per second.
Failure to follow these simple rules will result in inability to establish communication with the
instrument or intermittent failures in communication.
6.2.6
Changing Baud Rate
To use the Serial Interface, you must first set the Baud rate. Press
Interface
key to display the
following screen.
Select
−
With
−
°®
Baud
−−
9600
Press the
s
or
t
key to cycle through the choices of 300, 1200, or 9600 Baud. Press the
Enter
key
to accept the new number.
6-16
Remote Operation
