This Document is not yet Rated

Rate this Document

Digital Multimeters with Switches in Large Chassis

Hardware: Modular Instruments>>Digital Multimeters (DMM)

Problem: I have an 18-slot PXI chassis that will be using more than 10 switch modules with a DMM. Can I use the NI-DMM/Switch Express VI to perform my measurements?

Solution:

A DMM can be used with multiple switches as long as the switches are in the same segment of the chassis. This limitation is due to the PXI bridges between slots 6 to7 and 12 to 13. Triggers being routed between the DMM and switch can only propagate in one direction. This limits the user to a maximum of 5 switches in the same segment with one DMM or 4 for the first segment.

Figure 1. Allowable configurations for Express VI

In order to use multiple segments, the DMM and Switch triggers need to be assigned to two different trigger lines. These lines will have to be configured in Measurement and Automation Explorer.  Refer to the KnowledgeBase linked below for details on how to configure triggers across a PXI bridge. If the DMM is in the first segment the trigger routes should look like Figure 2.

Figure 2. Trigger Routes

 

Related Links: KnowledgeBase 32GFMIWD: Routing PXI Trigger Lines Across the Buses of Multisegment PXI Chassis
KnowledgeBase 3BK9FL0M: Programmatically Routing PXI Trigger Lines Across a Multi Segment PXI Chassis


Attachments:


- config.JPG
- two segment.JPG


Report Date: 01/10/2007
Last Updated: 09/17/2008
Document ID: 459K5SLQ

Your Feedback!	Poor  |  Excellent							Yes	No
Document Quality?							Answered Your Question?
	1	2	3	4	5
Document needs work? Please tell us why.
Please Contact NI for all product and support inquiries.