Functional Description

3B45-02/46-01 #2 The 3B45 and 3B46 are single-channel isolated frequency input modules which produce simultaneous precision voltage and current outputs proportional to input frequency. Model 3B45 accepts full-scale inputs ranging from 25 Hz to 1100 Hz, while Model 3B46 accepts full-scale inputs from 520 Hz to 25 kHz. Both models enable the user to set the threshold to either 0 V (for zero crossing signals) or +1.6 V (for positive level signals), and the hysteresis to either 0 or ± 4 V. Hysteresis can be set for any value within this range using the optional AC1310 ranging card. The 3B45 and 3B46 shield their computer side outputs from damage and loss of signal integrity from field-side overvoltage faults, withstanding up to 220 V rms at their input terminals. The current output withstands 130 V rms without damage and interfaces user equipment through screw terminal connections. In addition, all 3B45 and 3B46 models are plug-in, mix-and-match and hot-swappable, so each can be inserted or removed from any socket in the same backplane without disrupting system power.

3B Series Custom-Ranging Program

Externally-programmable Models 3B45-00 and 3B46-00 enable the user to configure a special input range by using the optional plug-on AC1310 ranging card, which houses user-supplied resistors to determine hysteresis, zero and span. To facilitate selecting resistors, a Windows® program, 3B-CUSTOM, calculates resistor values based on the user-desired input/output ranges.

Inside the 3B45 and 3B46 Series Module

The 3B45 and 3B46 compare the input signal to the user-selected threshold (Vt) and hysteresis (Vh). Signals of virtually any wave shape that exceed the combined threshold and hysteresis levels (Vt ± Vh) will trigger a comparator at a rate determined by the input frequency. The comparator output is then transmitted across a proprietary transformer-coupled isolation barrier. A demodulator on the computer side of the signal transformer recovers the original signal, which is then filtered and buffered to provide a low-noise, low-impedance output voltage; this output also drives a voltage-to-current (V/I) converter to provide a simultaneous current output for interfacing versatility.

Simple setup and versatile choices

Setting the threshold value is a simple matter of externally wiring to the 3B Series backplane screw terminals. The threshold for measuring a zero-crossing voltage waveform (such as sine waves) can be set to 0 volts by connecting terminal 3 connected to terminal 4. The threshold for a positive level signal (such as a TTL or pulse train waveform) can be set at +1.6 V by connecting terminals 1 and 2. Hysteresis for both input signal types is set at 0 V, but can be changed to ±4 V by removing the jumper that is installed on the AC1310 ranging card.

3B45,46FBD WIP

Figure 1. 3B45 and 3B46 Functional Block Diagram

3B45 WIP

Figure 2. 3B45 and 3B46 Input Field Connections



0 to 300 Hz

0 to 25 kHz

Dual Outputs

0 to +10 V

0 to 20 mA or 4 to 20 mA

3B45 and 3B46 Models Available

  Model Input Range Output Ranges1 Step Response
Order Now 3B45-00 Externally Programmable2 0 V to +10 V & 0 mA to 20 mA  
Order Now 3B45-01 0 Hz to 25 Hz 0 V to +10 V & 0 mA to 20 mA 1.6 sec
Order Now 3B45-02 0 Hz to 300 Hz 0 V to +10 V & 0 mA to 20 mA 0.6 sec
  3B45-Custom * *  

  Model Input Range Output Ranges1 Step Response
Order Now 3B46-00 Externally Programmable2 0 V to +10 V & 0 mA to 20 mA  
Order Now 3B46-010 kHz to 1.5 kHz 0 V to +10 V & 0 mA to 20 mA 0.07 sec
Order Now 3B46-02 0 kHz to 3 kHz 0 V to +10 V & 0 mA to 20 mA 0.03 sec
Order Now 3B46-03 0 kHz to 25 kHz 0 V to +10 V & 0 mA to 20 mA 0.03 sec
  3B46-Custom * *  

1 Output current range may be user programmed to 4 mA to 20 mA using jumper supplied.
2 Requires AC1310 ranging card.
* Custom Input/Output ranges are available. Refer to configuration guide.

3B45 and 3B46 Specifications
(typical @ +25°C and ±15 V dc, and +24 V dc Power)

Refer to Model Table
Description Model 3B45 Model 3B46
Input Ranges
Standard Ranges Refer to Model Table
Custom Ranges 25 Hz span, min : 1100 Hz span, max. 520 Hz span, min : 25 kHz span, max.
Output Ranges
Voltage (RL > 2 kΩ) 0 V to +10 V *
Current (RL + 0 to 850 Ω)1 4 mA to 20 mA or 0 mA to 20 mA *
   Maximum Current Output Span 0 mA to 31 mA *
Initial @ +25°C ±0.1% Span *
Nonlinearity ±0.02% Span *
Stability vs. Temperature
Voltage Output
   Output Zero ±500 µV/°C *
   Span ±50 ppm of Reading/°C *
Current Output3
   Zero ±25 ppm of Span/°C *
   Span ±25 ppm of Reading/°C *
Zero and Span Adjustment Range4 ±5% of Span *
Input Bias Current +3 nA *
Input Resistance
Small Signal, Vin < 4 V pk-pk 15 MΩ *
Large Signal, Vin > 4 V pk-pk 82 kΩ *
Output, 100 kHz Bandwidth 75 µV rms *
Output, Ripple 10 mV rms @ 10% Fspan, maximum *
Output Step Response Time Refer to Model Table *
Common-Mode Voltage (CMV)
Input-to-Output, Continuous ±1500 V peak, maximum *
Transient ANSI/IEEE C37.90.1-1989 *
Common-Mode Rejection (CMR)
1 kΩ Source Imbalance, 50/60 Hz 100 dB *
Input Protection
Continuous 220 V rms maximum *
Transient ANSI/IEEE C37.90.1-1989 *
Voltage Output Protection Continuous Short to Ground *
Current Output Protection 130 V rms, continuous *
Power Supply Voltages5
±15 V dc Supplies
   Rated Operation ±(11.5 V dc to 16.5 V dc) *
   Current ±16 mA ±19 mA
   Sensitivity ±0.01% span/V *
+24 V dc Loop Supply
   Rated Operation +13.5 V dc to +30 V dc *
   Current +27 mA @ lout = 20 mA *
   Sensitivity ±0.0002% span/V *
Mechanical Dimensions 3.15" x 3.395" x 0.775"
(80.0 mm x 86.2 mm x 19.7 mm)
Temperature Range
   Rated Performance -25°C to +85°C *
   Storage -55°C to +85°C *
Relative Humidity 0 to 95% @ +60°C noncondensing *
RFI Susceptibility ±0.5% Span error @ 400 MHz, 5 Watt, 3 ft *

* Specifications same as model 3B45.
1 For a 0 to 20 mA range, a typical minimum output current is 10 µA.
2 Includes the combined effects of repeatability, hysteresis, and nonlinearity.
3 With respect to the voltage output.
4 A wide range of custom zero suppression and span is available with the 3B45-00 and 3B46-00 models, using the AC1310 ranging card.
5 +24 V dc loop power is required for driving the current output at loads up to 850Ω. If a current output load of 400Ω or less is applied, +15 V dc is sufficient for loop power. If only voltage output is used, loop power is not required.
Specifications subject to change without notice.

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