LJTick-InBuff (LJTIB) 는 LabJack 제품에 pH sensors 를 직접 측정하고 다른 종류의 약한 신호를 측정할 수 있도록 하는 제품입니다.

LabJack DAQ 제품 (U3, U6, UE9, and T7) 는 10 ~ 100pA 의 전류가 필요합니다. 이 악세사리는 사용자가 10MΩ 이상의 소스 임피던스를 가진 신호를 측정할 수 있도록 도울 수 있습니다.

LJTick-InBuff 는 텍사스 인스트루먼트 사의 OPA2140 를 추가 제품의 아날로그 입력과 센서 사이에 고정밀, 저잡음 OP 증폭을 제공합니다.

• 1pA bias current
• ±10V input & output range
• Has pads to optionally install gain resistors & input filter.

Common Applications

• Measuring PH sensors.

Figure 1: LJTick-InBuff

Figure 2: LJTick-InBuff with U3-LV

Screw Terminal Descriptions

VS: This is the same 5 volt output as the VS terminals on the LabJack itself. This is an output terminal, not an input. It can be used to provide 5 volt (nominal) power as needed.

GND: Same as LabJack ground (GND).

INA/INB: These input lines go through the Op Amps to have their signals amplified before being sent to a LabJack device.

 

LJTick-InBuff Hardware Block Diagram

Figure 3: LJTick-InBuff Schematic

 

LJTick-InBuff Schematic

Figure 4: LJTick-InBuff Schematic

 

Usage with the T4 or U3-HV

The T4 and U3-HV have a mix of high voltage analog inputs (±10 volt range) and low voltage analog inputs (±2.5/2.4 volt range).  Most input ticks are best used with the low voltage analog inputs, but the LJTick-InBuff is unique in that it has a ±10 volt output range and thus either type of analog input might be best depending on the range of the input signal.

 

Specifications:

Parameter	Conditions	Min	Typical	Max	Units
General
Input Voltage Range		-10		10	Volts
Temperature Range		-40		85	°C
Supply Voltage		4		5.25	Volts
Supply Current			28		mA
Input Bias Current			±0.5	±10	pA
Input Impedance			10^13		Ω
Input Capacitance			10		pF
Gain Accuracy
Offset Accuracy				±100	μV
Cutoff Frequency	0-5V Input Sine Wave		4.3		MHz
	±10V Input Sine Wave		120		kHz

 

 

For more specifications about the Op Amp used in the LJTick-InBuff refer to the Texas Instruments OPA2140 datasheet.