CR7 Specifications
CR7 Specifications
Electrical specifications are valid for over a -25° to +50°C range unless otherwise specified.
Analog Inputs
(723T or 723 Card specifications below;
726 ±50 V Card specifications discussed in
System Description)
Voltage Measurement Types: Single-ended or
differential.
Range and Resolution: Ranges are software
selectable on any input channel.
Full Scale
Resolution
Input Range (mV)
Differential Single-ended
±5000
166
µV
333
µV
±1500
50
µV
100
µV
±500
16.6 µV
33.3 µV
±150
5
µV
10
µV
±50
1.66 µV
3.33 µV
±15
500
nV 1000
nV
±5
166
nV
333
nV
±1.5
50
nV
100
nV
Accuracy of Voltage Measurements:
Differential: ±0.02% FSR (±0.01%, 0-40°C)
(e.g. ±0.02% FSR = ±2.0 mV for ±5 V range)
Positive single-ended: ±0.02% FSR
(±0.01%, 0-40°C) ±5 µV
Negative single-ended: ±0.03% FSR
(±0.015%, 0-40°C) ±5 µV
Transient Protection
High Frequency Pulse Mode
Minimum Pulse Width: 2 µs
Maximum Input Frequency: 250 kHz
Voltage Thresholds: The count is incremented
when the input voltage changes from below
1.5 V to above 3.5 V.
Maximum Input Voltage: ±20 V
Low Level AC Mode
This mode is used for counting the frequency
of low voltage, sine wave signals.
Input Hysteresis: 11 mV
Maximum AC Input Voltage (RMS): 20 V
Frequency Range:
Minimum AC Input Voltage
(mV RMS)
15
25
50
160
100
1,000
3,000
10,000
Digital Control Outputs
(725 Card)
Each card includes 8 digital control outputs.
Range: ±5 V
Resolution: 166 µV
Normal Mode Rejection: 70 dB (60 Hz with
slow differential measurement)
Accuracy: Same as voltage measurements.
Pulse Counters
(724 Card)
Pulse Counters per Card: 4
Maximum Counts per Interval: 32,767 (with
overrange detection)
Modes: Programmable modes are switch
closure, high frequency pulse, and low level AC.
Switch Closure Mode
Minimum Switch Closed Time: 1 ms
Minimum Switch Open Time: 4 ms
Maximum Bounce Time: 1.4 ms open without
being counted.
Data Storage: 18.8K values, standard; 280K
values, expanded.
Peripheral Interface: 9-pin, D-type connector
on the Control Module panel for connection to
storage module, card storage module,
multidrop interface, modem, printer, or RS-232
adapter. Baud rates selectable at 300, 1200,
9600, and 76,800.
to
to
to
to
Common Mode Rejection: > 140 dB (DC to 100 Hz)
Sustained Input Voltage without Damage:
≤ ±16 VDC
Memory: 24K ROM; 40K RAM, 709 Card
provides an additional 512K RAM.
1
1
1
1
Common Mode Range: ±5 V
Input Resistance: 2.5 GΩ typical
Processor: Hitachi 6303
Display: 8 digit LCD (0.5” digits).
Output Voltages (no load):
High: 5.0 V ±0.1 V
Low: < 0.1 V
Input Current Noise: 9 pA RMS (slow differential)
Control Module
Range (Hz)
Input Sample Rates: Fast A/D conversions are
integrated over 250 µs. Slow A/D conversions
are integrated over 16.67 ms for 60 Hz AC
rejection or optionally, 20.0 ms for 50 Hz AC
rejection. Differential measurements include
two conversions, one with reversed input polarity, to reduce thermal offset and common mode
errors. The following intervals do not include
the self-calibration measurement which occurs
once per instruction.
Input sample Typical input
rates
noise
ms/channel
nV/RMS
Fast Single-ended
2.9
350
Fast Differential
4.7
250
Slow Single-ended
22.0
43
Slow Differential
43.0
30
Fast Differential (TC) 7.9
250
Input Current: 100 pA max
All input and output connections to the I/O
Module are protected using spark gaps that
are rated to 10,000 A. The spark gaps are
connected directly to a heavy copper bar on
each input card with no more than 2 inches of
20 AWG copper wire.
I/O Module Interface: Optically isolated current
loops allow connection of up to 4 I/O Modules.
I/O Modules can be separated from the Control
Module by up to 1,000 feet.
Clock Accuracy: ±1 minute per month.
Analog Outputs
Maximum Program Execution Rate: System
tasks can be initiated in sync with real-time up
to 80 Hz.
(725 Card)
System Power Requirements
Each card contains 8 switched and 2 continuous
analog outputs.
Voltage: 9.6 to 15 VDC
Output Resistance: 400 Ω
Switched: Provides a precision voltage for
resistance measurement, then switches off
(high impedance). Only one switched output
can be active at a time.
Continuous: A preset voltage is held until
updated. Voltage degrades 0.17 mV every 7
seconds. All continuous analog outputs (and
digital control ports) can be active simultaneously.
Output Current: 25 mA at ±5 V, 50 mA at ±2 V
Resistance and Conductivity
Measurements
(Combination of 723 and 725 Cards)
Accuracy: ±0.01% of full scale bridge output
provided the matching bridge resistors are not
the limiting factor.
Measurement Types: 6-wire and 4-wire full
bridge, 4-wire, 3-wire, and 2-wire half bridges.
High accuracy, low impedance bridge
measurements are made ratiometrically with
dual polarity measurements of excitation and
output to eliminate thermal emfs. AC resistance and conductivity measurements use a
750 µs excitation pulse with the signal integration occurring over the last 250 µs. An equal
duration pulse of opposite polarity is applied
for ionic depolarization.
Typical Current Drain: 3.5 - 6 mA (minimum
system) quiescent, 16 mA during processing,
100 mA during analog measurement.
Internal Batteries: Sealed rechargeable with
2.5 Ahr capacity per charge.
Charging Circuit: Requires DC or rectified AC
voltage from 15 to 25 V. Thermal compensation is included to optimize charging voltage
according to ambient temperature.
External Batteries: Any 12 V external battery
can be a primary power source; internal batteries provide a backup while the external
batteries are changed.
Operation from AC Sources: An AC operated
battery charger is included with the enclosure
to maintain full charge on the batteries where
AC power is available. In the event of power
failure, the internal batteries will keep the
system operational for up to 5 days in most
applications.
Physical Specifications
Size:
ENC 7L
ENC 7F
ENC 7XL
17” x 12” x 6”
20” x 13” x 10”
19” x 19” x 10”
Weight:
~40 lbs (ENC 7F with 700X, 720, &
seven I/O cards).
Warranty
Three years against defects in materials and
workmanship.
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