6. Specifications 
  -- 8 10 30  
CR800 specifications are valid from ─25° to 50°C in non-condensing environments unless otherwise specified. Recalibration is recommended every three years.    Critical specifications and system 
configurations should be confirmed with a Campbell Scientific sales engineer before purchase. 
2.0 -- 8 10 30 
PROGRAM EXECUTION RATE 
2.1 -- 8 10 30 
10 ms to one day at 10 ms increments 
3.0 -- 8 10 30 
ANALOG INPUTS (SE 1–6, DIFF 1–3) 
3.0.1 -- 8 10 30 
Three differential (DIFF) or six single-ended (SE) individually 
configured input channels. Channel expansion provided by optional 
analog multiplexers. 
3.1.0 -- 8 10 30 
RANGES and RESOLUTION: With reference to the following 
table, basic resolution (Basic Res) is the resolution of a single A/D
conversion. A DIFF measurement with input reversal has better 
(finer) resolution by twice than Basic Res. 
3.1.1 -- 8 10 
±2500 
±250 
±25 
±7.5 
333 
33.3 
3.33 
1.0 
667 
66.7 
6.7 
2.0 
1
Range overhead of ≈9% on all ranges guarantees full-scale 
voltage will not cause over-range. 
2
Resolution of DIFF measurements with input reversal. 
3.2 -- 8 10 
ANALOG INPUT ACCURACY
3
: 
±(0.06% of reading + offset
3
), 0° to 40°C 
±(0.12% of reading + offset
3
), -25° to 50°C 
±(0.18% of reading + offset
3
), -55° to 85°C (-XT only) 
 
3.2.1 -- 8 10 30 
3
Accuracy does not include sensor and measurement noise. 
Offset definitions: 
Offset = 1.5 x Basic Res + 1.0 µV (for DIFF measurement w/ input 
reversal) 
Offset = 3 x Basic Res + 2.0 µV (for DIFF measurement w/o input 
reversal) 
Offset = 3 x Basic Res + 3.0 µV (for SE measurement) 
3.3 -- 8 10 30 
ANALOG MEASUREMENT SPEED: 
3.3.1 -- 8 10 
4
gration 
Type 
Inte- 
gration 
 
Settling 
with 
no 
with 
Input 
_60Hz
5
 
16.67 ms 
3 ms 
≈20 ms 
≈40 ms 
4
Includes 250 μs for conversion to engineering units. 
5
AC line noise filter 
3.4 -- 8 10 30 
3.4.1 -- 8 10 30 
INPUT-NOISE VOLTAGE: For DIFF measurements with input 
reversal on ±2.5 mV input range (digital resolution dominates for 
higher ranges): 
250 μs Integration: 0.34 μV RMS 
50/60 Hz Integration: 0.19 μV RMS 
3.4.2 -- 8 10 30 
INPUT LIMITS: ±5 Vdc 
3.4.3 -- 8 10 30 
DC COMMON-MODE REJECTION: >100 dB 
3.4.4 -- 8 10 30 
NORMAL-MODE REJECTION: 70 dB @ 60 Hz when using 60 
Hz rejection 
3.4.5 -- 8 10 30 
INPUT VOLTAGE RANGE W/O MEASUREMENT 
CORRUPTION: ±8.6 Vdc max. 
3.4.6 -- 8 10 30 
SUSTAINED-INPUT VOLTAGE W/O DAMAGE: ±16 Vdc max 
3.4.7 -- 8 10 30 
INPUT CURRENT: ±1 nA typical, ±6 nA max. @ 50°C; ±90 nA 
@ 85°C 
3.4.8 -- 8 10 30 
INPUT RESISTANCE: 20 GΩ typical 
3.4.9 -- 8 10 30 
ACCURACY OF BUILT-IN REFERENCE JUNCTION 
THERMISTOR (for thermocouple measurements): 
±0.3°C, -25° to 50°C 
±0.8°C, -55° to 85°C (-XT only) 
4.0 -- 8 10 30 
ANALOG OUTPUTS (VX 1–2) 
4.0.1 -- 8 
Two switched voltage outputs sequentially active only during 
measurement. 
 
4.0.2 -- 8 10 30 
RANGES AND RESOLUTION: 
4.1 -- 8 10 
 
Channel 
 
Range 
Resolu- 
tion 
Source 
/ Sink 
4.2 -- 8 10 
ANALOG OUTPUT ACCURACY (VX): 
±(0.06% of setting + 0.8 mV, 0° to 40°C 
±(0.12% of setting + 0.8 mV, -25° to 50°C 
±(0.18% of setting + 0.8 mV, -55° to 85°C (-XT only) 
 
4.4 -- 8 10 30 
VX FREQUENCY SWEEP FUNCTION: Switched outputs 
provide a programmable swept frequency, 0 to 2500 mV square 
waves for exciting vibrating wire transducers. 
 
3.5.0 -- 8 10 30 
PERIOD AVERAGE 
3.5.0a -- 8 10 30 
Any of the 6 SE analog inputs can be used for period averaging.   
Accuracy is ±(0.01% of reading + resolution), where resolution is 
136 ns divided by the specified number of cycles to be measured. 
INPUT AMPLITUDE AND FREQUENCY: 
3.5.1 -- 8 10 
 
Signal 
Min 
 
10 
33 
mV25 
mV7_5 
10 
5 
2 
2 
10 
62 
50 
8 
6
Signal to be centered around Threshold (see PeriodAvg() 
instruction). 
7
Signal to be centered around ground. 
8
The maximum frequency = 1/(twice minimum pulse width) 
for 50% of duty cycle signals. 
5.0 -- 8 10 30 
RATIOMETRIC MEASUREMENTS 
5.1 -- 8 10 
MEASUREMENT TYPES: The CR800 provides ratiometric 
resistance measurements using voltage excitation.    Three switched 
voltage excitation outputs are available for measurement of four- 
and six-wire full bridges, and two-, three-, and four-wire half 
bridges. Optional excitation polarity reversal minimizes dc errors. 
 
5.2 -- 8 10 
RATIOMETRIC MEASUREMENT ACCURACY
9,11
 
Note Important assumptions outlined in footnote 9: 
 
±(0.04% of Voltage Measurement + Offset
12
) 
 
5.2.1 -- 8 10 30 
9
Accuracy specification assumes excitation reversal for excitation 
voltages < 1000 mV.    Assumption does not include bridge resistor 
errors and sensor and measurement noise. 
 
11
Estimated accuracy, ∆X (where X is value returned from 
measurement with Multiplier =1, Offset = 0): 
BRHalf() Instruction: ∆X = ∆V
1/
V
X
. 
BRFull() Instruction
: 
∆X = 1000 x ∆V
1/
V
X
, expressed as mV•V
-
1
. 
Note ∆V
1
 is calculated from the ratiometric measurement 
accuracy.    See manual section Resistance Measurements
 for more 
information. 
12
Offset definitions: 
Offset = 1.5 x Basic Res + 1.0 µV (for DIFF measurement w/ input 
reversal) 
Offset = 3 x Basic Res + 2.0 µV (for DIFF measurement w/o input 
reversal) 
Offset = 3 x Basic Res + 3.0 µV (for SE measurement) 
Note Excitation reversal reduces offsets by a factor of two. 
6.0 -- 8 10 30 
PULSE COUNTERS (P 1–2) 
6.0.1 -- 8 10 30 
Two inputs individually selectable for switch closure, high-
frequency pulse, or low-level ac. Independent 24-bit counters for 
each input. 
6.1 -- 8 10 30 
MAXIMUM COUNTS PER SCAN: 16.7 x 10
6
 
6.2 -- 8 10 30 
SWITCH CLOSURE MODE: 
Minimum Switch Closed Time: 5 ms 
Minimum Switch Open Time: 6 ms 
Max. Bounce Time: 1 ms open without being counted 
6.3 -- 8 10 30 
HIGH-FREQUENCY PULSE MODE: 
Maximum-Input Frequency: 250 kHz 
Maximum-Input Voltage: ±20 V 
Voltage Thresholds: Count upon transition from below 0.9 V to 
above 2.2 V after input filter with 1.2 μs time constant. 
6.4 -- 8 10 30 
LOW-LEVEL AC MODE: Internal ac coupling removes dc offsets 
up to ±0.5 Vdc. 
Input Hysteresis: 12 mV RMS @ 1 Hz 
Maximum ac-Input Voltage: ±20 V 
Minimum ac-Input Voltage: 
6.4.1 -- 8 10 30 
200 
2000 
0.5 to 200 
0.3 to 10,000 
 
7.0 -- 8 10 30 
DIGITAL I/O PORTS (C 1–4) 
7.0.1 -- 8 10 30 
Four ports software selectable as binary inputs or control outputs. 
Provide on/off, pulse width modulation, edge timing, subroutine 
interrupts / wake up, switch closure pulse counting, high-frequency 
pulse counting, asynchronous communications (UARTs), and SDI-
12 communications. SDM communications are also supported.   
7.1 -- 8 10 30 
LOW FREQUENCY MODE MAX: <1 kHz 
7.2 -- 8 10 30 
HIGH FREQUENCY MODE MAX: 400 kHz 
7.3 -- 8 10 30 
SWITCH-CLOSURE FREQUENCY MAX: 150 Hz 
7.4 -- 8 10 30 
EDGE-TIMING RESOLUTION: 540 ns 
7.5 -- 8 10 30 
OUTPUT VOLTAGES (no load): high 5.0 V ±0.1 V; low < 0.1 V 
7.6 -- 8 10 30 
OUTPUT RESISTANCE: 330 Ω 
7.7 -- 8 10 30 
INPUT STATE: high 3.8 to 16 V; low -8.0 to 1.2 V 
7.8 -- 8 10 30 
INPUT HYSTERISIS: 1.4 V 
7.9 -- 8 10 30 
INPUT RESISTANCE: 
100 kΩ with inputs < 6.2 Vdc 
220 Ω with inputs ≥ 6.2 Vdc 
7.10 -- 8 10 30 
SERIAL DEVICE / RS-232 SUPPORT: 0 to 5 Vdc UART 
 
7.12 -- 8 10 30 
SWITCHED 12 Vdc (SW12) 
One independent 12 Vdc unregulated terminal switched on and off 
under program control. Thermal fuse hold current = 900 mA at 
20°C, 650 mA at 50°C, and 360 mA at 85°C. 
8.0 -- 8 10 30 
COMPLIANCE 
8.1 -- 8 10 30 
View the EU Declaration of Conformity at 
www.campbellsci.com/cr800 
9.0 -- 8 10 30 
COMMUNICATION 
9.1 -- 8 10 30 
RS-232 PORTS: 
DCE nine-pin: (not electrically isolated) for computer connection 
or connection of modems not manufactured by Campbell 
Scientific. 
COM1 to COM2: two independent Tx/Rx pairs on control ports 
(non-isolated); 0 to 5 Vdc UART 
Baud Rate: selectable from 300 bps to 115.2 kbps. 
Default Format: eight data bits; one stop bits; no parity. 
Optional Formats: seven data bits; two stop bits; odd, even parity. 
9.2 -- 8 10 30 
CS I/O PORT: Interface with comms peripherals manufactured by 
Campbell Scientific. 
9.3 -- 8 10 30 
SDI-12: Digital control ports C1, C3 are individually configurable 
and meet SDI-12 Standard v. 1.3 for datalogger mode.    Up to ten 
SDI-12 sensors are supported per port. 
 
9.5 -- 8 10 30 
PROTOCOLS SUPPORTED: PakBus, AES-128 Encrypted 
PakBus, Modbus, DNP3, FTP, HTTP, XML, HTML, POP3, 
SMTP, Telnet, NTCIP, NTP, web API, SDI-12, SDM. 
10.0 -- 8 10 30 
SYSTEM 
10.1 -- 8 10 30 
PROCESSOR: Renesas H8S 2322 (16-bit CPU with 32-bit internal 
core running at 7.3 MHz) 
10.2 -- 8 10 30 
MEMORY: 2 MB of flash for operating system; 4 MB of battery-
backed SRAM for CPU, CRBasic programs, and data. 
10.3 -- 8 10 30 
REAL-TIME CLOCK ACCURACY: ±3 min. per year. Correction 
via GPS optional. 
10.4 -- 8 10 30 
RTC CLOCK RESOLUTION: 10 ms 
11.0 -- 8 10 30 
SYSTEM POWER REQUIREMENTS 
11.1 -- 8 10 30 
VOLTAGE: 9.6 to 16 Vdc 
11.2 -- 8 10 
INTERNAL BATTERY: 1200 mAhr lithium battery for clock and 
SRAM backup. Typically provides three years of back-up. 
 
11.3 -- 8 10 30 
EXTERNAL BATTERIES: Optional 12 Vdc nominal alkaline and 
rechargeable available.  Power connection is reverse polarity 
protected. 
11.4 -- 8 10 30 
TYPICAL CURRENT DRAIN at 12 Vdc: 
Sleep Mode: 0.7 mA typical; 0.9 mA maximum 
1 Hz Sample Rate (one fast SE meas.): 1 mA 
100 Hz Sample Rate (one fast SE meas.): 16 mA 
100 Hz Sample Rate (one fast SE meas. with RS-232 
communications): 28 mA 
Active external keyboard display adds 7 mA (100 mA with 
backlight on). 
12.0 -- 8 10 30 
PHYSICAL 
12.1 
DIMENSIONS: 241 x 104 x 51 mm (9.5 x 4.1 x 2 in.)   ; additional 
clearance required for cables and leads. 
12.2 
MASS / WEIGHT: 0.7 kg / 1.5 lbs 
13.0 
WARRANTY 
13.1 
Warranty is stated in the published price list and in opening pages 
of this and other user manuals.