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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