RS PRO RM-804 Ohmmeter, 5 MΩ Max, 1μΩ Resolution, 4 Wire

RS PRO RM-804/805 Series High Precision Programmable DC Milliohm Meters

RS PRO RM-804/805 Series DC milliohm meter models which offer Handler, RS-232C and USB device interfaces. Options available (RM-804, 122-5158 ) plus option 01 GPIB (RM-804-01, 122-5157 ) or standard GPIB (RM-805, 122-5156 ). These milli-ohmmeters are ideal for calculating low resistance at high precision to verify the value of the electrical circuit.


These ohmmeters provide better display interface, fast measurement (60 readings per second) and collocate with standard communications interface (RS-232C/USB device) to facilitate users in obtaining measurement tasks quickly. These instruments have two measurement speed selections which are Fast (60 readings per second) and Slow (10 readings per second). The reading resolution will not be changed by changing speed and the display digits remain the same.


Model RM-805 (122-5156) offers drive modes DC+/DC-, Pulsed, PWM, Zero, for measurement applications on different materials. Pulsed current output mode reduces thermal EMF influence. DC+ and DC- output modes are best for measuring inductive components. PWM output mode, ideal for temperature-sensitive materials, can avoid resistance value variation due to overload on current measurement over time.


Model RM-805 (122-5156) also offers dry circuit which can limit applied voltage, under the open circuit voltage of 20 mV, to avoid over voltage occurring on both ends of components.


RS Pro RM-804/805 Series provides a D-sub 25-pin combined interface to connect Handler, Scan or EXT IO to a sorting machine, connect with an external on-off switch and enable external trigger control. These ohmmeters offer faster measurement with sacrificing the resolution.

Features and Benefits

• 50 000 counts


• 3.5 inch (320 x 240) TFT LCD display


• High accuracy, 0.05% precision


• 1 A test current, 1 μΩ resolution


• Fast measurement, 60 readings per second


• Four wire resistance measurement


• Temperature compensation measurement function


• Delayed measurement


• 20 sets of panel setting memory


• Interface - USB device, RS-232C, Handler/Scan/EXT I/O, and GPIB (option)

Typical Applications

Ohmmeters are electrical instruments that measure electrical resistance of a circuit. There are various types of meters available with different sensitivity levels which include micro, mega and milli ohmmeters. These RS PRO meters are milliohmmeters and can be used for:

• Production testing for contact resistance of switches, relays, connectors, cables, printed circuit boards and other low resistance devices


• Component testing of resistors, motors, fuses and heating elements


• Incoming inspection and quality assurance testing


• Conductivity evaluation for product design

Why choose RS PRO?

RS PRO is our own brand of high-quality products whilst bringing you great value for money. Our wide range of products have been engineered to meet high industry standards, so you are ensured reliable and robust solutions.

Supplied with

Quick start guide, power cord, test lead, user manual on CD