User`s manual

8 . 1 G e n e ra l 131
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Chapter 8: Service
8.1 General
This chapter provides basic service information for the Model 335 temperature con-
troller. Customer service of the product is limited to the
information presented in this
chapter. Factory trained service personnel should be consulted if the instrument
requires repair.
8.2 USB
Troubleshooting
This section provides USB interface troubleshooting for issues that arise with new
installations, existing installations, and intermittent lockups.
8.2.1 New Installation
1. Check that the USB driver is installed properly and that the device is functioning.
In Microsoft Windows®, the device status can be checked using Device Manager
by right-clicking Lake Shore Model 335 Temperature Controller under Ports
(COM & LPT) or Other Devices and then clicking Properties. Refer to 
section 6.3.3 for details on installing the USB driver.
2. Check that the correct com port is being used. In Microsoft Windows®, the com
port number can be check
ed using Device Manager under Ports (COM & LPT).
3. Check that the correct settings are being used for communication. Refer to 
section 6.3.3 for details on installing the USB driver.
4. Check cable connections and length.
5. Send the message terminator.
6. Send entire message string at one time includin
g the terminator. (Many terminal
emulation programs do not.)
7. Send only one simple command at a time until communication is established.
8. Be sure to spell commands correctly and use proper syntax.
8.2.2 Existing
Installation No Longer
Working
1. Power the instrument off, then on again to see if it is a soft failure.
2. Power the computer off, then on again to see if comm
unication port is locked up.
3. Check all the cable connections.
4. Check that the com port assignment has not been changed. In 
Microsoft Windows®, the com port number can be checked using Device Manager
under Po
rts (COM & LPT).
5. Check that the USB driver is installed properly and that the device is functioning.
In Micr
osoft Windows®, the device status can be checked using Device Manager
by right-clicking Lake Shore Model 335 Temperature Controller under Ports
(COM & LPT) or Other Devices and then clicking Properties.
8.2.3 Intermittent
Lockups
1. Check cable connections and length.
2. Increase delay between all commands to 100 m
s to make sure the instrument is
not being overloaded.
3. Ensure that the USB cable is not unplugged and that the Model 335 is not pow-
ered down while the com port is open. The USB driver creates a com port when
the U
SB connection is detected, and removes the com port when the USB connec-
tion is no longer detected. Removal of the com port while it is in use by the soft-
ware can cause the software to lock up or crash.