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RS PRO RS 135, 24mA Current Loop Calibrator

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RS PRO Current Loop Calibrator and Thermometer

For all current loop repair, calibration and maintenance needs RS PRO presents an easy to use solution. This loop calibrator offers grade precision for temperature measurement and calibration accuracy with a wide measurement range. Source and measure current loops simultaneously. Featuring a clear and easy to read LCD screen, this product is also user friendly and ergonomic with soft touch buttons, built in stand and easy to use settings.

Applications include calibration of 4∼20 mA panel meters, LED brightness testing and temperature calibration of instruments or panel meters for 11 types of thermocouples.

Features and Benefits:

• Source 4∼20 mA, 0∼24 mA with 1 μA resolution (1 KΩ load, 24 V loop supply), basic accuracy 0.025%
• Source 0∼24.000 V with 1 mV resolution
• Source frequency 1∼20000 Hz square wave with programmable duty cycle (1∼99%)
• Auto step and auto ramp for sourcing mA, V
• Easy fixed 25% up and down, or programmable percentage (1∼99%) increase and decrease (mAV)
• Measure DC mA with loop power (24 V output)
• Measure DC V
• Measure Temperature (°C, °F) of 11 types of thermocouples (K, J, E, T, R, S, N, L, U, B and C)
• Calibrator grade precision temperature measurement with 0.1°C & 0.1°F resolution
• Detection of thermocouples disconnection
• Warning for overload, output open (mA) or short (V)
• Short circuit protection for output
• Battery power indication (%) when turn on the calibrator
• Battery or electrical power supply


Current loop calibrators are versatile devices used to simulate the operation of loop powered transmitters, source current to unpowered devices in a loop and measure current. With features such as microprocessor based electronics and digital interfaces, they make excellent troubleshooting tools for circuits. Current loop calibrators are commonly used in areas such as:

• Research and development
• Servicing
• Process control engineering
• Calibration technician


What thermocouple types can this work with?

This current loop calibrator with temperature measurement can work with 11 types of thermocouples including K, J, E, T, R, S, N, L, U, B and C.

How much current flows in each loop of a parallel circuit?

Determined by Ohm's law, which states that the current between 2 points through a conductor is directly proportionate to the voltage across those 2 points, divided by the resistance of the conductor. I = V/R. This is also the case for series and parallel circuits, however in parallel circuits the total current can be affected by the way the resistors have been connected, as well as their ohmic value. Current does divide up and there can be more current in one area over another nonetheless when all areas are added up the total amount is the same.

What is included?

• User manual
• Carrying case
• 5 x 1.5 V SUM-3 battery
• K-type thermocouples (1m, single plug)
• 2 x Aligator clips (black and red)
• 2 x test leads (black and red)

Absolute Maximum Current Measurement24mA
Best Accuracy±0.025 % ±5 digits
Resolution1 μA
Battery Type1.5 V SUM-3
Power SourceBattery, Mains
Dimensions98.7 x 56 x 214mm
Maximum Operating Temperature+50°C
Minimum Operating Temperature0°C
Model Number pRS 135