Datasheet

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A GREATER MEASURE OF CONFIDENCE
Model 7708 Specifications
SWITCH/MEASURE SYSTEMS
31
Integra Series Multimeter/Switch Systems
Modules
7708 40-CHANNEL DIFFERENTIAL MULTIPLEXER
MODULE
FEATURES
• 40 differential channels for general-purpose measurements.
• 2- or 4-wire measurements.
• Oversize screw terminal connection blocks are standard for easier connection.
• 300V, 1A capacity for voltage channels; 60W, 125VA.
• Configurable as two independent banks of multiplexers.
• Built-in CJC sensors automatically linearize thermocouples.
• Relay closures stored in on-board memory.
GENERAL
40 CHANNELS: 40 channels of 2-pole relay input. All channels configurable to 4-pole.
RELAY TYPE: Latching electromechanical.
ACTUATION TIME: <3ms.
FIRMWARE: Specified for Model 2700 rev. B02, 2701 rev. A01, and 2750 rev. A01
or higher.
CAPABILITIES
CHANNELS 1–40: Multiplex one of 40 2-pole or one of 20 4-pole signals into DMM.
INPUTS
MAXIMUM SIGNAL LEVEL:
Channels (1–40): 300V DC or rms, 1A switched, 60W, 125VA maximum.
CONTACT LIFE (typ): >10
5
operations at max. signal level.
>10
8
operations cold switching.
CONTACT RESISTANCE: <1Ω at end of contact life.
CONTACT POTENTIAL: <±500nV typical per contact, 1µV max.
<±500nV typical per contact pair, 1µV max.
OFFSET CURRENT: <100pA.
CONNECTOR TYPE: Screw terminal, #20 AWG wire size.
ISOLATION BETWEEN ANY TWO TERMINALS: >10
10
Ω, <100pF.
ISOLATION BETWEEN ANY TERMINAL AND EARTH: >10
9
Ω, <200pF.
CROSS TALK (10MHz, 50Ω Load): <–40dB.
INSERTION LOSS (50Ω Source, 50Ω Load): <0.1dB below 1MHz.
<3dB below 2MHz.
COMMON MODE VOLTAGE: 300V between any terminal and chassis.
TEMPERATURE ACCURACY USING INTERNAL CJC: 1.0°C (see mainframe specifica-
tion for details).
ENVIRONMENTAL:
OPERATING ENVIRONMENT: Specified for 0°C to 50°C.
Specified to 80% R.H. at 35°C.
STORAGE ENVIRONMENT: –25°C to 65°C.
WEIGHT: 0.52kg (1.16 lb).
ACCESSORIES AVAILABLE:
Model 7401 Type K Thermocouple Wire, 30.5m (100 ft).
Channel 1
HI
LO
Channel 20
HI
LO
(Channels 2–19)
Channel 21
HI
LO
Channel 40
HI
LO
(Channels 22–39)
HI
LO
Sense
HI
LO
Input
Channel 43
2-Pole / 4-Pole
(see Note)
To Model 2700,
2701, or 2750
Backplane
Channel 45
(see Note)
Backplane
isolation
Channel 44
(see Note)
Backplane
isolation
NOTE Channels 43–45 in this schematic
refer to the designations used for
control and not actual available channels.
For more information, refer to the
ROUTe:MULTiple command section
in the Model 2700, 2710, or 2750 User’s Manual.
Card Sense
HI
LO
Card Input
HI
LO
Cold Junction
Ref XY
Cold Junction
Ref XY