Racks and chassis

A benchtop DMM is one instrument at one address. A PXI chassis is a frame holding modules, each of which does something different, and a rack is a frame holding whole instruments. TestFlow configures each of these in place, and the generated code addresses the right thing.

Switching chassis

Pickering and National Instruments modular switching.

1. 1

   Add a Switch

   Under Digital & Control. Pick the manufacturer and the chassis model.
2. 2

   Populate the slots

   Choose a module per slot from that vendor’s module catalog. Modules that span more than one slot occupy the slots they physically occupy.
3. 3

   Give the chassis its address

   The chassis has the address. The modules do not.

A crosspoint module is addressed the same way, by slot and then by coordinates:

Switch    Connect Crosspoint   slot 2, x 3, y 7

Power mainframes

A modular supply where each rear bay is a channel.

Add the mainframe, then fit a power module per bay. The bay position is the channel number the commands address, so bay 2 is channel 2 and there is nothing to map by hand. Each module carries its own voltage, current, and power envelope, and the mainframe carries a total power budget the fitted modules have to fit inside.

ATE racks

A container that holds whole instruments, not modules.

A rack is configured by placing instruments into its bays and then configuring each one in place, exactly as you would if it were standalone. It can also hold a nested chassis, so a rack containing a PXI frame containing modules works.

What this means for your workflow

• Modular hardware usually has no SCPI catalog, which makes it a special instrument: the codegen agent writes its driver.
• One special instrument on the bench switches the whole package onto the generated-driver path, and you will be asked to approve that driver before it first runs.
• Removing the last special instrument switches you straight back to deterministic compilation.