Ventilation Standards For Small Mammals; Ttl Start/Stop Command; Synchronised Start/Stop Model 7125 - UGO BASILE 7025 Series Instruction Manual

4.4

Ventilation Standards for Small Mammals

For a deeper evaluation of all the parameters involved in the artificial ventilation of exper-
imental animals, we suggest the operator to read the basic paper on this subject: L.I.
Kleinman & E.P. Radford: "Ventilation Standards for Small Mammals" J. Appl. Physiol.
19(2): 360-362, 1964 (copies are available on request).
4.5

TTL Start/Stop Command

Delicate electrophysiological-pharmacological investigations may require that the animal
"holds its breath" for a while, to minimize all movements.
For this purpose, operation of the Ventilator may be "paused" by an external TTL logic
signal, provided by miniature jacks to fit 2mm banana plugs located on the control panel
(see Figure 3 "Front Panel").
A voltage signal, 3 to 25V amplitude, RED JACK positive (max. current drain at 25V = 2.5
mA), causes the Ventilator to stop. Restarting takes place when the signal drops to zero!
Accidental reversing of polarity will not activate the circuit but causes no damage.
A special circuit has been designed, to minimize the mechanical-electrical inertia and
electromagnetic interference which would be unavoidable via crude ON-OFF power
switching.
Pause timing ought not to be too long nor too frequent. Compensating a pause with a
faster rate may help;
For more demanding electrophysiological-pharmacological investigations, An optional
synchronised command is available to START-STOP the Ventilator, see following par-
agraph.
4.6

Synchronised Start/Stop Model 7125

The operation of Ventilator may be "paused" by an external TTL logic signal. This feature,
available on model 7125 (see paragraph 8-ORDERING INFORMATION) is particularly
useful when the operation of the Ventilator is software controlled.
This special model of Rodent Ventilator is provided with optimal synchronous stop fea-
ture; you will notice two BNC connectors on the left side panel of the Ventilator case.
The BNC marked "SYNCHRON" supplies a square pulse (5V amplitude, 20ms duration)
at each ventilator stroke, when the piston is at the upper dead point (i.e., when the piston
almost touches the cylinder bottom and the lungs are inflated.)
This trigger signal can inform/command a number of recording and/or actuating devic-
es. To obtain the synchronous stop, it is necessary to send a 5V pulse (grounded nega-
tive) to the STOP BNC-connector, for at least 5s.
The Ventilator will automatically restart after a 5 second time interval.
pause when the lungs are
7025 Instruction Manual (Rev. 2)
full.
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