Lake Shore Model 218 Temperature Monitor User’s Manual
6-10
Remote Operation
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.
Press the
s
or
t
keys to cycle through the choices of 300, 1200, or 9600 Baud. Press
Enter
to
accept the new number.
