Multichannel Systems PPS2 Manual - Manual (Page 14)

Peristaltic Pump Manual
12
Stop
The “On” and “Off” buttons will affect one pump of the PPS2. The “Stop” button will always
stop both pumps. If several pumps are connected with a serial cable, all connected pumps will
be stopped.
Bubble Detector
The bubble detector can be used as an alarm system to prevent flooding of the recording
equipment. A light barrier detects the changes of fluid to air in the outlet tube and measures
whether this event takes place at least once every ten seconds or not. More than one bubble
per 10 seconds is considered okay, less is considered as an indicator that the fluid flow in the
outlet is too low. The LED is constantly on without tube, when the fluid flow is not correct it
flashes fast, with correct flow the LED flashes slowly.
Select the check box “Use Bubble Detector” to use the function of the bubble detector.
The detector is only active while the pump is running and the “Bubbles” button turns to
green “Startup”.
When fluid flow in the outlet tube is too low or too high, the bubble detector stops the
inlet perfusion pump automatically. The waste pump runs continuously to prevent overflow.
The button turns to red “No”.
External Control: Digital (TTL) and Analog Mode
External control via analog input or digital TTL input allows the same functions as the manual
mode or the controlling via touch screen without software. You can use different modes for
each pump.
The pump speed is still selected in PPS2 software, and the pump status has to be “On”,
as the state of the external input and the pump state are in an logical AND relation:
Digital Mode: The digital input must be “high” AND the pump must be “On” to start
the pump.
Analog Mode: The analog input must be > 0.0 V AND the pump must be “On” to start
the pump.