LR Series Pen Recorders (DISCONTINUED)

Recording Functions

1600 mm/s Maximum Pen Speed

For the fastest possible response, Yokogawa developed new proprietary technologies for the LR Series, and raised the maximum pen speed to 1600 mm/s, nearly twice that of the previous fastest. In terms of frequency response, this equates with nearly 3 Hz at full deflection and 6 Hz at small deflections. High-speed signals are thus recorded faithfully.

Disposable Felt-Tipped Pens

The newly developed recording pens of the LR12000E are special disposable felt-tipped pens with a long thin pen arm and a wide ink storage section, to enable the pens near the back of the instrument to be more visible. These pens have the same high-speed response and long life as conventional LR series pens.

Auto Sweepout of Pen Offset Data

When you use pen offset compensation, the recorder stores data to compensate for the pen offsets in order to record all traces in real-time. Thus when recording stops, the pens must continue recording until all the data is plotted. Auto sweepout saves you time by automatically increasing the chart speed during this interval - a real advantage at slow chart speeds. For example, at 10 mm/h chart speed on an 8-pen LR, it would take nearly three hours after measurement to record all the stored offset data. In the current LR Series recorders, however, touching the chart stop key automatically increases the chart speed to 200 mm/min and stops it after all pen offset data have been swept out. This takes just eight seconds. This new function, not available on previous LR recorders, has been added at the request of many users.

Floppy Disk Drive

Install the floppy disk drive option (FDD) and you can save the LR recorder settings to several files on a floppy disk (FD). The measurement data can also be saved to FD via the internal buffer memory provided by the FDD option. Various memory functions, including data saving, triggers, pre-triggering, auto-save/load to and from FD, and ASCII conversion all come with the FDD option. 

• Auto-save
• When saving measurement data, this function automatically copies the data to a FD after the data has been acquired by the internal buffer memory.
• Auto-load
• When loading measurement data, this function copies the data saved on a FD to the internal buffer memory, then automatically outputs to the recording paper from the data in the internal buffer memory.
• Copying measurement data to FD
• Specify either binary or ASCII format when copying data from the internal buffer memory to a FD.

IC Memory Card

• Save settings for permanent storage (standard function)
• By saving recorder settings such as range to an IC memory card, you can retrieve them later and start recording immediatelyuicker than re-setting the parameters one by one. The standard 8 KB memory card can store two setting files from the LR12000E, three from the LR8100E, and five from the LR4100E or LR4200E.
• Capture Detailed Measurement Data (optional function)
• The optional IC memory cards with 256 KB or more (sold separately) let you capture and store up to 32,000 samples/channel. The data can be retrieved later in a variety of ways, and up to 47 files of settings can be stored. With the LR trigger functions, you can use the card not only for simple data storage and playback, but also as a backup memory to avoid losing data if a chart runs out during a run, or as a buffer to capture data ahead of the trigger when waiting for an alarm or other trigger event.
• IC Memory Card Reader
• With the dedicated IC memory card reader (3781), you can use an office personal computer to read the IC memory card and analyze the stored data measured by an LR series recorder at the site or laboratory.

Universal Inputs

Universal inputs let you wire DC voltage, thermocouple, or RTD inputs directly to the input terminal and begin recording simply by selecting the sensor type and range from the front panel; no longer do you have to waste time with external temperature converters, or with changing input modules for different sensor types.
There are 20 ranges for DC voltage, down to 0.1 mV sensitivity, and for temperature you can select from 12 types of thermocouple and 5 types of RTD. In the cryogenic region, gold-iron chromel (KPvsAu7Fe) and platinum-cobalt (J263*B) RTDs can measure from 0 to 300 K *1.
*1: 0 K = -273.15 degrees Celsius.

Computing Functions

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.

LR's Advanced Recording Technology

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.

Brushless DC Motors/Optical Rotary Encoders

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.

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.

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

Digital Servos...2-Stage Control Alorithm

The LR Series recorders employ an advanced digital servo system. An ASIC* single-chip microcomputer and gate array is provided for each pen, with the servo control algorithms stored in the microcomputer ROM.

The pulse signals from the optical magnetic pole sensor and optical encoder are received by encoder interface circuits on the gate array. After signal processing there, they are counted by an up/down counter in the microcomputer to compute the pen position and motor speed. Command signals for motor speed and commutation timing are then applied to the PWM** circuits according to the control algorithm, and the resulting pulse signals control the motor driver circuits that handle coil current commutation.
This servo system uses a new 2-stage control algorithm. In the first stage of positioning a nonlinear control algorithm called "Bang-Bang" is used for fast positioning. This has the shortcoming that variations in the mechanical parameters near the target make it prone to limit cycling, hampering fine positioning. The 2-stage algorithm overcomes this problem by switching near the target value to PID control, which is stable even at high positioning accuracy.

The combination of this 2-stage control algorithm with the high torque gained from the high-performance rotor magnet has increased the pen speed and frequency response by a factor of two compared with earlier Yokogawa products.

*ASIC: Application Specific IC
**PWM: Pulse Width Modulation

Improved Recording Mechanisms

The LR Series recorders feature new techniques in the recording pens and platen, too. The disposable felt pens used on earlier models have been made smaller, lighter and longer-life by integrating the ink reservoir with the pen arm and expanding the ink capacity. This has doubled the recording life of our earlier pens.
The LR12000E recorder, for example, employs slimmer pen arms and wider ink reservoirs, enabling clear viewing even to the twelfth pen. This model has an ink storage capacity as large as that of the recording pens of other LR Series recorders, achieving high visibility, reduced weight and longer service life.

Conventional recorders also suffer from faint or broken traces at high writing speed (the vector sum of the pen speed and chart feed rate), and blotting and tearing of the paper at slow speeds.
For the LR Series, therefore, new inks were specially developed for high- and low-speed recording, and one of three pen types can be selected to suit the writing speed, greatly reducing the risk of blotches and paper tears. Another improvement is a slot in the platen, which solves the problem of low-speed ink blotting along the folds (lines of perforations) in the chart. 

Intelligent Input Modules

The LR Series input circuits feature intelligent signal conditioners using a separate ASIC microprocessor as the controller for each channel.

High accuracy measurement: To reduce the high-sensitivity amp offset in the voltage divider and amplifier sections, which handle levels from 100 au F.S. to 200 V F.S., the internal zero error is A/D converted, and an offset voltage is provided by the D/A converter in the auto canceler. The gain error of the potential divider and amplifier are measured with high accuracy during production and written to a non-volatile semiconductor memory for use in calibration compensation. Auto calibration is performed before each measurement by applying zero and full-scale inputs to the A/D converter.

Noise immunity
Noise immunity is a major performance criterion for lab-use recorders, which must operate in severe environments. Thus, the microprocessor performs digital filtering in addition to analog filtering, for even greater rejection of normal mode noise. The common mode noise influence is drastically reduced by totally isolating each circuit from all others with photocouplers and individual floating power supplies.

High reliability
Semiconductor technology is used extensively throughout the circuits for the highest reliability. For example, scale and zero adjustment pots, a frequent cause of failure, have been replaced by calibration data written into nonvolatile memory. In addition, the input circuitry is protected at all times by circuitry that senses overvoltages due to incorrect connections and switches the voltage divider to prevent damage.

Sophisticated measurement
All thermocouple and RTD inputs are digitally linearized, and thermocouple zero point compensation is performed digitally using a transistor temperature sensor in the terminal board. The universal input circuits digitize at a 135 Hz rate.

Noise Suppression Testing

With the increasing use of digital technology in the electronic circuits of measuring instruments, good noise immunity is essential. Noise itself is difficult to represent quantitatively, and noise in the field is often sporadic. If noise gets through to the microprocessor section, program execution may be disturbed, resulting in "run away"; in a recorder, this may cause a pen to lock up at one side of the chart, or cause an erroneous digital value to be displayed, or disrupt chart feed.

Yokogawa has designed evaluation tests with fixed test conditions through which noise immunity can be verified. Although various noise tests are conducted, a test using high-frequency pulse noise to which digital systems are especially susceptible is described below. This test attempts to cause operating errors by applying a 1 ns rise-time pulse (time for pulse to rise from 10 to 90% of its peak value), which can cause malfunctions as it enters the circuits through stray capacitances. The noise bandwidth in this test reaches several GHz, making this the most difficult form of noise to protect against. In the Figure 6, an LR8100E is being tested for noise immunity by applying high-frequency pulse noise to its input terminals in common mode. In this example, there was no disturbance to the digital subsystems even with the maximum output of 1 kV peak. Similar tests have been performed for noise introduced in the power supply lines as well, using different test equipment, and no program execution errors have occurred even at peak values up to 2 kV.

Bearing Profile Measurement

IC Memory Card

The surface irregularities of a bearing rotating at high speed are converted to voltages by a sensor and recorded on an LR Series recorder. Because the speed of bearing rotation cannot be slowed for this measurement, data is captured first to an IC memory card at a fast sampling rate of 135 Hz. On playback the readout rate is set to 3 Hz, recording the surface profile on a time axis expanded by 135/3 = 45 times for analysis.

Electrolytic Capacitor Saturation

Print via Remote Control

A voltage of 750 V is applied to an electrolyte used in capacitors, and the saturation characteristic curve is drawn for each position on the test material. Although with conventional analog recorders it was possible to read from the chart the voltage remaining after some elapsed time, by combining an LR recorder and a timer the numeric values can be printed out automatically.

Copy Machine Power Supply Performance Test

Universal Input, Communications Functions

Tests the effect of power supply voltage variations on copy machine performance. The test parameters (voltage, frequency) are varied using a power supply simulator, and the temperatures and circuit voltages in the copy machine are input directly to an LR recorder. The power supply simulator and LR recorder settings are uploaded the computer together with the measurements via GP-IB communications to analyze machine performance under voltage variations.

Pilot Process Analysis

Universal Input, PC Communications

By recording temperatures, pressures, flowrates and other variables in a pilot process on an LR Series recorder, the data can then easily be uploaded to a personal computer via a GP-IB link while monitoring them on the recorder. The process characteristics can then be analyzed on the computer.

Features		Models	LR12000E	LR8100E	LR4100E		LR4200E
					LR4110	LR4120	LR4210	LR4220
Form		Vertical					Flatbed
Recording Width		250 mm
No. of Pens		10, 12		4, 6, 8	1, 2, 3, 4
Input Ranges		Voltage (20 ranges): 0.1 mV to 200 V Thermocouple (12 types) R, S, B, K, E, J, N, T, W, L [DIN], U [DIN], KPvsAU7Fe RTD (5 types): PT100, JPt100, Pt50, Ni100, J263*B
Printing Functions		Periodic print, manual print, change of range print, message print, change of chart speed print, pen offset compensation ON/OFF print, alarm print, scale marking print, and program list print. *Printing functions not provided in LR4120 and LR4220.
Display		Digital Values, Bar graph (2.5% resolution), Range
		Switches between display of the first-half 6 pens and the second-half 6 pens. *1		All channels, simultaneous easy-to-read fluorescent screen.
Math		Standard: Scaling Function, Difference Computation
		Optional:*3 Arithmetic operations, exponentials, logarithms, absolute value, square root
IC Memory Card*3		8 KB, 256 KB, 512 KB, 1 MB, (8 KB card provided as standard)
FDD*3 (option)		Built-in FDD with 768 KB RAM		Built-in FDD with 512 KB RAM	Built-in FDD with 256 KB RAM
PC Software		Can be used with all models for 4-pen, 8-pen, 12-pen applications.
Chart Speed		10 to 600 mm/min 10 to 600 mm/hour		10 mm/hour to 1,200 mm/min
Chart Length		Z-fold: 30m			Z-fold: 20m		Z-fold: 20 m; Roll: 20m
Power		Allowable voltage: 90 to 132 V AC/180 to 250 V AC (automatic switching) 48 to 63 Hz Rated Voltage: 100 to 120 V AC / 200 to 240 V AC 50/60Hz
				+10 to +32 V DC (optional)