LR12000E / LR8100E / LR4100E / LR4200E

The standard LR recorders can perform scaling computations on all channels, or record the differences between channels. By adding the MATH option*, you can define up to eight expressions using arithmetic operators, square roots, absolute values, logarithms, exponentials, and parentheses. You can assign the result to be recorded in real-time with one of the pens, or write it to the IC memory card or floppy disk, or transmit it through the communications interface like regular measurement data.
If the computations can be done using these expressions, a personal computer may not even be needed for analysis -the LR recorder can perform the computations alone. And by adding the internal alarm (/AK-0n) option, the recorder can even generate contact outputs when a computed result exceeds the high or low limit.
* MATH option not available for the LR12000E.

The LR Series state-of-the-art recorders embody the most advanced recording technology that we have developed in shipping more than one million recorders over the last forty years. Yokogawa design has always been based on two key principles: recording quality (accuracy and clarity of the recorded trace), and reliability (minimum failure and prolonged lifespan). All functions and performance are built on these two cornerstones.

Yokogawa has led the waves of each revolution in advanced recording technologies, as exemplified by the introduction of microcomputers (intelligent recorders), brushless DC motors, and ultrasonic pen position sensing. The LR Series marks a new milestone in recorder design with widespread use of semiconductor technology to reduce the number of moving parts and mechanical contacts to an absolute minimum.

The heart of a recorder is its servo system. This used to be the weak point of these instruments, such as the reduction gear train, and sliding contact between brushes and commutators in DC motors, and between sliders and pen position sensing slide wires. Mechanical wear, contact failure, play and backlash in these areas adversely affected reliability and durability (See below).

In most DC motors, the polarity of the magnetic field produced in the rotor is switched back and forth relative to that in the stator according to the shaft rotation, generating torque due to attraction and repulsion between stator and rotor. To switch the rotor magnetic field, the direction of current flow through the coils of the rotor must be switched as it turned, and this is traditionally done by brushes and a commutator.
The pen position sensor, on the other hand, senses the amount of motor rotation to determine the pen position. "Rotational angle measurement" is the principle of both commutator control and pen position sensing, and achieving this without sliding contacts eliminates two of the major obstacles to better reliability. The third obstacle "the gear train" can be eliminated if the motor torque can be made high enough to work without reduction gearing, while still achieving sufficiently fine rotational angle control.

For the LR Series, Yokogawa has developed a proprietary DC motor which overcomes all these obstacles. It uses an assembly of an optical rotary encoder for angle sensing and an optical magnetic pole sensor to detect the rotation staring point; the signals from these sensors are processed in digital control circuits to carry out both coil current switching and pen position sensing. This technique makes the DC motor brushless and integrates the potentiometric functions (See above).

A high-performance rotor magnet eliminates the gear train by generating the high torque needed for direct drive operation (See below).
By eliminating the sliding contacts and meshing gears from the main parts of the servo system, reliability is greatly improved.

A high-performance rotor magnet eliminates the gear train by generating the high torque needed for direct drive operation (See below).

By eliminating the sliding contacts and meshing gears from the main parts of the servo system, reliability is greatly improved.