Computer Interfacing
The ValveLink8.2 can be controlled from a computer using its digital
inputs, analog input or USB port. AutoMate Scientific supplies free
software for communicating over the USB port, but the digital and analog
inputs require you to provide software to generate the signals. Most
customers use their data acquisition software like Axon Instruments'
"pClamp" or Heka's "Pulse." General I/O software like "LabView" from
National Instruments also works well.
You can directly control individual ValveLink8.2 valves from your
computer using one digital output per valve, or you can control all eight
valves with just three digital outputs using Mode #2 or 3 described in
the "Modes" chapter. Computer digital signals are also called "TTL" for
Transistor-Transistor Logic. An "on" or "high" signal is +5V and "off" or
"low" is zero volts. Almost any analog output can also produce these
two voltages. Therefore, if you do not have enough digital outputs, then
analog outputs can also be used to drive the ValveLink8.2 when set to
5 or 0V. When the input goes high, a valve opens, and when it
drops low, the valve closes again.
While AutoMate Scientific generally does not support software or
hardware from other companies, we have accumulated some instructions
for connecting the ValveLink8.2 to pClamp software and DigiData
hardware from Axon Instruments. These instructions may help even if you
are using other software.
1) Connect one or more pClamp/DigiData digital outputs to the
corresponding ValveLink8.2 digital inputs (and ground) using the wiring
diagram on page 18 of this manual, or an AutoMate Scientific-supplied
BNC cable. DigiData digital outputs 0-3 appear as BNC connectors on the
front panel. Digital outputs 4-7 are located on the back panel of newer
DigiData interfaces. Older DigiData 1200’s only have four outputs.
2) The ‘Modes’ chapter explains the two different methods of controlling
valves: Demultiplexed or not.
3) You can manually generate digital outputs 0-3 from Clampex using the
‘Real Time Control Panel’ adjacent to the ‘Scope’ window. Click the four
checkboxes to turn the outputs on or off and test your connection.
4) To program the digital outputs from pClamp you have two choices:
Sequencing Keys/User Lists or Waveform - Epochs.
Sequencing Keys/User Lists:
Clampex lets you program activities as “Sequencing Keys” (Config menu)
which can include digital outputs (Operations tab / Parameters / Digital
Out Bit Pattern). The Sequencing Keys can be assigned to hot keys or
grouped together into “User Lists” (Acquire menu / New Protocol /
Stimulate / User List). Each Sequencing Key becomes one ‘step’ in your
perfusion/recording experiment, and can be assigned a time duration.
It is also possible to link Sequencing Keys into a series without needing
User Lists. You can also program a “Digital Holding Level” (Lab Bench /
Configure / Overrides) which maintains a valve state between protocols.
Waveform - Epochs:
The bottom of each Epoch column on the Protocol / Waveforms screen
offers a set of four digital bit patterns. This way you can program valve
activity for each recording epoch interval.
Also see the “Scenarios” section of the “Experiments” chapter of your
pClamp manual. The “Isolated Patch-Clamp Single-Channel Recording”
section (manual page 125 or 135) describes triggering with a drug
application system (DAS).
Contact AutoMate Scientific for advice on how to program your computer
to control valves, or to purchase cables for connecting the ValveLink8.2 to
your I/O hardware.
AutoMate Scientific
®
R E A D Y F O R R E S E A R C H.
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