Keithley 2700, Service Manual

Page: 128 / 174

A-8 Specifications
Cold junction
Ref x3
Channel 1
HI
LO
Channel 10
HI
LO
(Channels 2–9)
Channel 11
HI
LO
Channel 20
HI
LO
(Channels 12–19)
Channel 21
HI
LO
Channel 22
HI
LO
AMPS
HI
LO
Sense
HI
LO
Input
Channel 23
2-Pole (Open)
4-Pole (Closed)
(see Note)
3A
3A
To Model 2700
Backplane
Channel 25
(see Note)
Backplane
isolation
Channel 24
(see Note)
Backplane
isolation
NOTE Channels 23–25 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 User’s Manual.
Channels 24 and 25 can be individually
controlled using ROUTe:MULTiple if the
module is not to be connected to the
internal DMM.
Card
AMPS
LO
Card Sense
HI
LO
Card Input
HI
LO
Cold junction
Ref x3
GENERAL
20 CHANNELS: 20 channels of 2-pole relay input. All channels config-
urable to 4-pole.
2 CHANNELS: 2 channels of current only input.
RELAY TYPE: Latching electromechanical.
ACTUATION TIME: <3ms.
CAPABILITIES
CHANNELS 1-20: Multiplex one of 20 2-pole or one of 10 4-pole signals
into DMM.
CHANNELS 21-22: Multiplex one of 2 2-pole current signals into
DMM.
INPUTS
MAXIMUM SIGNAL LEVEL:
Channels (1-20): 300V DC or rms, 1A switched, 60W, 125VA maxi-
mum.
Channels (21-22): 60V DC or 30V rms, 3A switched, 60W, 125VA
maximum.
CONTACT LIFE (typ): >10
5
operations at max signal level.
>10 8 operations cold switching.
CONTACT RESISTANCE: <1
Ω
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, 50
Ω
Load): <–40dB.
INSERTION LOSS (50
Ω
Source, 50
Ω
Load): <0.1dB below 1MHz.
<3dB below 2MHz.
COMMON MODE VOLTAGE: 300V between any terminal and chassis.
T/C COLD JUNCTION: 1.0°C (18°–28°C Mainframe Temp)
1.5°C (0°–18°C & 28°–50°C Mainframe Temp).
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: 0.45kg (1 lb).
7700 20-Channel Differential Multiplexer w/Automatic CJC