Posted in | Accelerometers

Force Balance Accelerometers: Biaxial Sensors

The Columbia SA-220RHT and SA-225RHT Force Balance Accelerometers are designed to be used as Measurement While Drilling (MWD) sensors in downhole well servicing applications. The Model SA-220RHT is powered by ±15 VDC and can withstand temperatures of up to 200 °C.

The model SA-225RHT runs at 190 °C and requires ±5 VDC. Both sensors are self-contained and give a high-level, low-impedance output, avoiding the need for signal conditioning at high temperatures.

The SA-220RHT and SA-225RHT sensors have become the established standard used in downhole high-temperature mapping because of their remarkable high-temperature performance, tough design and low power consumption.

  • Choice of power options
  • 200 °C and 190 °C operation
  • Biaxial sensors

Force Balance Accelerometers: Biaxial Sensors

Image Credit: Columbia Research Laboratories, Inc.

Specifications

Operational

Table 1. Source: Columbia Research Laboratories, Inc.

Operational SA-220RHT SA-225RHT
Ranges Available ±1 G to ±10 G ±1 G to ±5 G
Output Voltage ±5 Volts ±2%
Into 100 K Load
±3 Volts ±2%
Into 100 K Load
Excitation ±15 VDC
<40 mA
±5 VDC
<20 mA
Case Alignment <0.5°
Non-Linearity ±0.05% F.R. ±0.10% F.R.
Hysteresis ±0.07% F.R. ±0.15% F.R.
Non-Repeatability ±0.10% F.R. ±0.15%FR.
Resolution <0.001% F.R. <0.002% F.R.
Zero Bias ±0.15% F.R. ±0.25% F.R.
Zero Bias Temp. Coefficient ±0.002% F.R./°C ±0.003% FR/°C
Scale Factor Temp. Coefficient ±0.025%/°C
Natural Frequency 50 Hz to 300 Hz
Dependent on Range
50 Hz to 250 Hz
Dependent on Range
Damping Ratio 0.6 to 1.0 0.7±0.2
Cross Axis Sensitivity 0.01 G/G

 

Environmental

Table 2. Source: Columbia Research Laboratories, Inc.

Environmental SA-220RHT SA-225RHT
Temperature, Operating -40 to +200 °C -40 to +190 °C
Temperature, Storage -50 to +200 °C
Random Vibration (2 to 2000 Hz) 25 G RMS, 0.5'' Disp. D.A
Shock Survival 500 G, 0.5 mS

 

Physical

Table 3. Source: Columbia Research Laboratories, Inc.

Physical SA-220RHT SA-225RHT
Weight 3.34 oz (94.7 gm)
Size 1.13"Sq. x 2.285"H (2.9 cm Sq x 5.8"H)
Case Material Nickel Plated Aluminum
Sealing Environmental
Electrical Interface (Standard)  6 Terminal Pins

 

Vertical Mounting Plate Columbia P/N AFB04418P01.

Vertical Mounting Plate Columbia P/N AFB04418P01. Image Credit: Columbia Research Laboratories, Inc.

Horizontal Mounting Plate Columbia P/N AFB04418P02.

Horizontal Mounting Plate Columbia P/N AFB04418P02. Image Credit: Columbia Research Laboratories, Inc.

I/O Connector Pin Functions

Table 4. Source: Columbia Research Laboratories, Inc.

SA-220RHT
Pin Function
1 +15 VDC
2 Ground
3 -15 VDC
4 X Output
5 Ground
6 Y Output
Pins 2 & 5 are common ground to pwr supply and both outputs

Table 5. Source: Columbia Research Laboratories, Inc.

SA-225RHT
Pin Function
1 +5 VDC
2 Ground
3 -5 VDC
4 X Output
5 Ground
6 Y Output
Pins 2 & 5 are common ground to pwr supply and both outputs

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