Datasheet

1.888.KEITHLEY (U.S. only)
www.keithley.com
5
SWITCHING AND CONTROL
A GREATER MEASURE OF CONFIDENCE
MULTIPLEXER CONFIGURATION: Two independent 1×30 2-pole multiplexers. Banks can be
isolated from the backplane by relays. Card can be configured for 2 and 4 wire.
CONTACT CONFIGURATION: 2 pole form A.
CONNECTOR TYPE: Two 78 pin male D-shells.
MODEL 3720-ST SCREW TERMINAL OPTION: #22 AWG typical wire size with 0.062 inch O.D.
124 conductors maximum. #16 AWG maximum wire size with 0.092 inch O.D. 36 conductors
per card maximum.
MAXIMUM SIGNAL LEVEL: Channels 1–60: 300V DC or RMS, 1A switched (2A carry), 60W, 125VA.
COMMON MODE VOLTAGE: 300V DC or RMS between any terminal and chassis.
VOLT-HERTZ LIMIT: 8×10
7
.
CONTACT LIFE: >10
5
operations at maximum signal level. >10
8
operations no load.
1
Dual 1×30
3
Single 1×60
2, 3
Channel Resistance (end of contact life)
<1.0
W <1.5 W
Contact Potential (differential)
<±1 μV <± 3 μV
Offset Current
<±250 pA <±250 pA
Isolation
Differential
10
9
W , 250 pF 10
9
W , 450 pF
Bank-Bank
10
10
W , 75 pF —
Channel-channel
10
9
W , 75 pF 10
9
W , 75 pF
Common Mode
10
9
W , 200 pF 10
9
W , 400 pF
Crosstalk Channel-channel
300kHz
<–60 dB <–55 dB
1MHz
<–50 dB <–50 dB
20MHz:
<–25 dB <–20 dB
Bandwidth
30 MHz 10 MHz
TYPICAL SCANNING SPEEDS:
Switch Only
4
: Sequential scanning, single channel, immediate trigger advance: >120 ch/s.
With Measurements Into Memory
5
:
DCV (10V range) or 2W Ohms (1k
W range): >110 ch/s.
Thermocouple: >110 ch/s.
3- or 4-Wire RTD: >100 ch/s.
4-Wire Ohms (1k
W range): >100 ch/s.
ACV (10V range): >110 ch/s.
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
Output 1
HI
LO
Channel 1
HI
LO
Channel 30
Channels 2–29
Multiplexer Bank 1
Analog
Backplane 1
(DMM Input)
Analog
Backplane 2
(DMM Sense)
Analog
Backplane 3
Analog
Backplane 4
Analog
Backplane 5
Analog
Backplane 6
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
HI
LO
Output 2
HI
LO
Channel 31
HI
LO
Channel 60
Channels 32–59
Multiplexer Bank 2
Analog
Backplane 1
(DMM Input)
Analog
Backplane 2
(DMM Sense)
Analog
Backplane 3
Analog
Backplane 4
Analog
Backplane 5
Analog
Backplane 6
To Series 3700A Mainframe Analog Backplane
GENERAL
ACTUATION TIME: 4ms.
TEMPERATURE ACCURACY using Automatic CJC with 3720-ST accessory: 1°C for J, K, T
and E types (see mainframe specification for details).
RELAY TYPE: Latching electromechanical.
RELAY DRIVE SCHEME: Matrix.
INTERLOCK: Backplane relays disabled when interlock connection is removed.
OPERATING ENVIRONMENT: Specified for 0° to 50°C. Specified to 70% R.H. at 35°C.
STORAGE ENVIRONMENT: –25° to 65°C.
WEIGHT: 2.5 lbs.
SAFETY: Conforms to European Union Directive 73/23/EEC, EN61010-1.
EMC: Conforms to European Union Directive 2004/108/EC, EN61326-1.
NOTES
1. Open detector enabled during thermocouple measurements. Minimum signal level 10mV, 10μA.
2. 3706A mainframe with all DMM backplane relays disconnected. Maximum two card backplane relays closed.
3. Connections made using 3720-ST accessory.
4. Scanning script local to 3706A mainframe, within same bank, and break before make switching.
5. 3706A mainframe with autorange off, limits off, dmm.autozero=0, dmm.autodelay=0, 4½ digits (NPLC=0.006),
for ACV dmm.detectorbandwidth=300, for OHMs dmm.offsetcompensation=off, dmm.opendetector=off.
Scanning script local to mainframe, sequential scan within same bank (2 pole) or card (4 pole), and break
before make switching.
3720
Dual 1×30 Multiplexer Card
60 differential channels, automatic CJC w/3720-ST accessory
100% duty
50% duty
25% duty
10% duty
5% duty
1 shot
20
10
1
0.1 110100
Pulse Width (ms)
1. Model 3706A ambient temperature <28°C.
2. One shot repetition rate > 10 seconds.
3. Signal path routed only through one card (not through backplane).
4. Only one channel closed at a time.
5. Contact life specification unaffected if pulse width and carry current are not exceeded.
Maximum Carrying Current (A)
Maximum Carrying Current for Pulses
1000 10000
Model 3720 specifications Model 3720 specifications