Agilent Technologies 3499A/B/C Scan Feature, Single Scan List Size, Scan Rate, Modules, Ch/s

Scan Feature

The scan feature is a sequence of alternating switch closures and measurements. This feature is provided by both the 34980A and a 3499A/B/C combined with a DMM or other measurement instrument. The 34980A increases the measurement scan abilities and offers more than twice the number of scanned channels within one scan list compared to the 3499A/B/C as seen here.

Single Scan List Size:

34980A	Up to 560
	2-wire channels
	or
	Up to 640
	1-wire channels
3499A/B/C	Up to 200 channels
	and/or bits

Although the 34980A scan feature can be used with either the internal DMM or with an external instrument, using the integrated DMM provides a faster and more efficient scan rate. The integrated DMM eliminates the need for external instrument triggers and wiring. The 3499A/B/C scan list requires the use of instrument triggers to work with an external DMM or other measurement instrument. Each switch module is rated with individual switch scan rates. A comparison of the scan rates for both systems Multiplexer and Matrix switch modules is shown in Table 5 below.

Another advantage the 34980A system has over the 3499A/B/C system is its ability to store measurement readings. When the 34980A internal DMM is used, up to 500,000 time stamped readings can be stored in volatile memory.

The 3499A/B/C cannot store readings but does offer more scan configurability. For example, once a 3499A/B/C scan list is set up, the user can select an arm source, a trigger source, the number of sweeps, and the delay time for each individual channel within the scan list.

Table 5. 34980A and 3499A/B/C Multiplexer & Matrix module scan rates
	Module Type
		34980A		Scan Rate	3499A/B/C		Scan Rate
		Modules		Ch/s	Modules		Ch/s
	Multiplexer	34921A 40 Ch armature		100	N2260A 40 Ch armature		80
		34922A	70 Ch armature	100	N2266A 40 Ch reed		350
		34923A	40 Ch reed	500	N2270A 10 Ch		100
		34924A	70 Ch reed	500	44470A	10 Ch armature	43
		34925A	40 Ch FET	1000	44470D	20 Ch armature	43
	Matrix	34931A Dual 4x8 armature		100	N2262A 4x8 armature		80
		34932A Dual 4x16 armature		100	44473A	4x4 armature	43
		34933A Dual 4x8 reed		500

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