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SPECIFICATIONS for i100, i100B and i100HC

Fig 6.2 Model 100xx Network Device Connector  Layout.

Digital I/O

This is a digital I/O port consisting of 8 individual lines, each of which can be configured as either a digital input channel or a digital output channel.  When configured as an input, a channel can be used to sense a digital high (3.2V to 10Volts) or digital low (0 to 1Volts).  When configured as an output a channel can be set high (2.0V min) or low (.5V max).  The inputs are protected against high voltages up to +12Volts and down to -12V, before permanent damage occurs to internal circuitry.

Parameter Specification
Digital I/O 8 non-latching input bits and 8 latching output bits at 8 bidirectional screw terminals
Input Levels  VIH = 3.2V min ... 12V max
VIL = 1.0V max ... -12V min
VIL = 1.0V max ... -12V min
IIH = -200µA, Vi = 3.2V
IIL = -.5mA max.
Output Levels VOH = 2V min ... 5V max
IOH = -.5mA max.
IOL = 500mA max, VO=1.7V
IOL = 50mA max, VO = .7V

Table 6.2 Model 100, 100B, and 100HC Technical Specifications.

Analog Voltage Input (A/D)

These are voltage input ports that can be wired for many different types of sensors.   When wiring single-ended inputs the Vin+ and Vin- terminals function identically.

Parameter Specification
A/D Conversion Time 4µs min
A/D Resolution 14-bit
Voltage Input Range 

±5V, ±.6V, ± 78mV max (80 typ), ± 8mV max (10 typ)

Amplifier Gain 1, 8, 64, 512
Number of Channels 16se/8di
System Throughput 166Ksamples/second max
Signal To Noise Ratio 78dB
Differential Linearity ± 1.5 LSB
Integral Linearity ± 2 LSB
Over voltage Protection ± 15 V (power on or off)
Input Impedance 10Mohm±1%, 3pf
Common Mode Voltage (CMV) ±5V min.
Common Mode Rejection (CMR) ± 80dB
Common Mode Rejection (CMR) ± 80dB
Temperature Drift Gain: ± 5ppm/°C of FSR
  Offset: Self-cal'ed to 0
Time Stability Gain: 27ppm/1yr typ
  Offset: Self-cal'ed to 0

Voltage Measurement Accuracy

Voltage Range  Integration
±5V 1ms
±0±.6V 1ms
±80mV 1ms
±10mV 1ms
  0sec accurate  
  0sec fast  

1Measurement Accuracy: 0-70°C, no condensation, #iNet-100xx Rev 3, temperature has not changed since self-calibration, Accuracies are typical within 2 standard deviations.  Accuracy is effected by the Channel Switching field (i.e. set in the Setup dialog to Accurate or Fast) and the integration time.  If the Channel Switching field is set to Accurate, the signal is given more time to settle after the channel multiplexor is switched.  Accurate switching has a lower maximum sample rate than Fast switching.

2Integration Time: Integration time is independently programmable for each channel, and reduces noise by averaging many samples.  Also, if more than 125 samples are averaged, a dithering noise generator automatically turns on to add noise to the input signal.   This increases the accuracy further by using more a/d codes to establish the input volt. For details, click here.

Thermocouple Measurement Accuracy with the i100

instruNet supports a direct connection to thermocouples with the following measurement accuracies. The table excludes thermocouple device errors; yet includes cold junction compenstation errors, voltage measurement errors, and linearization errors.

TC Type Temperature Range Accuracy (±°C)3
B 250C to 600C
600C to 1820C
C 0C to 2315°C 2.4
D 0C to 2315C 2.2
E -200C to -60C
-60C to 1000C
G 0C to 100C
100C to 300C
300C to 2315C
J -210C to -100C
-100C to 1200C
K -200C to -50C
-50C to 1372C
N -200C to -110C
-110C to 1300C
R -50C to 70C
70C to 1768C
S -50C to 150C
150C to 1768C
T -200C to -100C
-100C to 400C

3CONDITIONS: 18-28C ambient temperature around instruNet hardware, excludes thermocouple errors, 0.001 sec of integration, instruNet 100 #iNet-100 Rev 3, assumes temperature has not changed since instruNet 100 self-calibration.

Thermistor Measurement Accuracy with the i100

The instruNet 100HC supports the direct connection to YSI/Omega 4xx and 4xxxx series thermistors, requiring one external shunt resistor. The following table shows accuracies with 2 different kinds of shunt resistors (i.e. 0.025%-20ppm/C and 0.1%-25ppm/C resistor). The table excludes thermistor device errors; yet includes thermistor and shunt self-heating errors, shunt initial accuracy errors, voltage measurement errors, and linearization errors.

(ohms @ 25C)
Temp Range
R Shunt
±°C Accuracy4
R=.025% - 20ppm/C
±°C Accuracy4
R=0.1% - 25ppm/C
2252 -80 to 40C 47K 4.90V 0.2 0.24
  0 to 70C 4.7K 0.55V 0.1 0.12
  0 to 200C 200 0.55V 0.4 0.4
10000 -80 to 40C 100K 4.90V 0.3 0.32
  0 to 70C 10K 0.55V 0.1 0.12
  0 to 250C 2K 0.55V 0.16 0.18

4Conditions: 18-28C ambient temperature around instruNet hardware, excludes thermistor errors, 0.001 sec of integration, instruNet #iNet-100HC Rev 3, assumes temperature has not changed since instruNet 100 self-calibration.

Analog Voltage Output (D/A)

These are voltage output ports that can be used for purposes such as stimuli and sensor excitation.

Parameter Specification
D/A Resolution 8-bit
Number of Channels 8
Output Voltage Range #100/100B: ±5V, 4mA, .001uF
  #100HC: ±5V, 15mA, .01uF
Output Protection Short-to-ground continuous
Output Settling Time 4µs (to ±1/2 LSB,±5V step)
Analog Output Accuracy ±0.4%
Digital Coupling ±20mV
Gain Drift ± 10ppm/°C of 5V FSR
Offset Drift  ± 5µV/°C

Power Available to End User

The +5V, -12V, and +12V screw terminals can be used to power external devices.  The maximum allowed current specified in the below table should not be exceeded, else the controller and/or the computer could be damaged.  To power an external device, run a wire from a voltage output terminal (e.g. "+5V) to the device and also run a wire from one of the ground terminals (i.e. "GND") to the device ground.

+5V 100 mA max.
+12V  30 mA max.
-12V  30 mA max.

Network Interface

The Model 100 cables to a Controller and/or other Network Devices via DB-25 cables.

Parameter Specification
Network Utilization Occupies 1 physical address in instruNet Network
Compatibility All instruNet Controllers and Network Devices
Network Connector DB-25 male connector (input), DB-25 female connector (out)


All I/O signals cable to the Model 100 via screw terminals.

Parameter Specification
I/O Connector Screw Terminals
Dimensions 1.8" x 4.2" x 9"
Operating Temperature  0 to 70°C
Storage Temperature  0 to 70°C
Relative Humidity  Up to 90% (non-condensing)
Power Consumption5 +5V @ 180mA max
+12V @ 80mA max
-12V @ 80mA max

5Internal Power: Power consumed by the Model 100 Network Device without additional Network Devices attached, without a terminator, and without outputs loaded.  Total system power consumption is the sum of the power consumed by the Controller and each attached Network Device.

Stability and Drift

The instruNet 100 (part #iNet-100 or iNet-100B) has the following Stability and Drift Characteristics:

Gain Drift ± 7ppm-per-degree-C Maximum
Offset Drift: Calibrated to 0 during software Reset or AutoCalibration
Gain Stability: 1yr: 27ppm/1yr Typical, 50ppm/1yr Max
2yr: 39ppm/2yr Typical, 62ppm/2yr Max
Offset Stability: Calibrated to 0 during software Reset

The primary error from the i100 measurement electronics is an offset voltage of approximately 2uV/C that occurs at the analog voltage measurement input amplifier. This means you will get an offset error of approximately 2uV for every 1 degree C that the amplifier IC heats up. It heats approx 5C above ambient (air around instruNet box) when first turned on and stabilizes after 1hr or so. From here, the IC temperature changes as the room temperature changes (e.g. a 5C increase in room temperature will increase the IC temperature by 5C, which could add voltage measurement offset error of 10uV). When Auto Calibration is run, this error is eliminated to 0uV.

Auto-Calibrating the i100 While Digitizing

The i100 can automatically calibrate out thermal offset drift errors (e.g. 2uV offset error per 1C change in i100 box temperature) while digitizing. These errors are proportional to the temperature change since the last auto-calibration. For example, if we calibrate the i100 at 25C (i100 box temperature), and later the box temperature is 29C, then the Voltage inputs will produce measurement errors between -8uV and +8uV (2uV/C * 4C = 8uV). In many cases; this is not a problem; yet with strain gages, load cells and thermocouples; this could be an issue. In order for this auto-calibration of thermal offset errors (to zero error) while digitizing to operate, all the 40/4KHz analog filters must be off on all channels within the i100xx box being calibrated; and, there must be at least 6ms of time between the total integration time and the sample period. For example, if one digitizes 4 channels with 4ms integration each (16ms total), they would need a sample period of at least 20ms to support this feature. To see which channels are set up for auto-calibrate offset drift while digitizing, set up your recording, press the START button to digitize for several seconds, press STOP, enter "calibrate reportOn" in the BASIC page, press EXECUTE, and view the listed channels. If your list is empty, make sure your AUTO CAL RATE field is >0, make sure all 40/4KHz filters are off, and make sure at least one channel has a range <= ±80mV (large ranges are not affected.