Bio-Rad ChromLab™ Software - Manual (Page 60)

2 | The NGC Instrument
58 | NGC Chromatography Systems and ChromLab Software
Column Switching Valve LEDs
The column switching valve modules are fitted with LEDs.
 Solid green LEDs indicate the flow is from the system pump in the forward
direction.
 Blinking green LEDs indicate the flow is from the system pump in the
reverse direction.
 Solid blue LEDs indicate the flow is from the sample pump in the forward
direction.
 Blinking blue LEDs indicate the flow is from the sample pump in the
reverse direction.
 Blinking green LEDs indicate the line to plumb when using the
Point-to-Plumb feature.
How the Column Switching Valve Works
The NGC system supports up to three column switching valves. Each column
switching valve enables you to select from up to five attached columns. The top of
the column connects to a numbered port labeled Top. The bottom of the column
connects to the corresponding numbered port labeled Bottom. The active ports are
identified by LEDs.
By default (and for most applications) the buffer flows from the top of the column to
the bottom. When you select Reverse Flow in ChromLab, the flow travels from the
bottom to the top of the column. This is useful for column cleaning and applications
that require elution of concentrated bands. When the flow is reversed, the LEDs on
the active ports blink green when the reverse flow through the port is from the
system pumps. The LEDs blink blue when the flow is from the sample pump.
The column switching valve has three flow paths:
 Bypass
 Forward flow
 Reverse flow