WEIGHT TRANSMITTERS FOR SCALES

Model 1X3-1945 USB weight transmitter with Auto-Cal

With both power and data direct from the PC computer's USB port, RL Scale's 1X3-1945 weight transmitter allows PC applications to access weight or force readings from any load cell assembly with high precision and settling speed.  The transmitter has 24 bit resolution and typical noise/jitter of better than 1 part in 100,000 at settling times of second or less.  The latest development in ADC chips, a proprietary filtering technique and RL Scales' 40 years experience in load cell electronics make this possible.  A detailed application manual steers the user through the steps needed to interface the transmitter with software for the user's main application; engineering and software assistance is available on request.

The 1X3-1945 transmitter has been optimized for lowest noise and fastest settling together with high rejection of vibration frequencies;  all parameters can be preset from a PC 'dashboard' application.  This application also allows calibration,  monitoring of weight values, measurement of settling time, testing of commands (for reading the weight values and setting of operating parameters) and upgrades to the internal firmware.  The circuit board's internal firmware can also be modified on a custom basis for non-standard applications.

http://www.rlscales.com/images/RoHS-ok.gifA major feature of this transmitter is its ability to compensate for the variation of gravity with latitude and altitude.  A little known fact, the force of gravity decreases as the distance from the center of the earth increases. because the earth is spinning, it flattens out towards the equator, which is 43 km wider in diameter than at the poles.  This can cause up to 0.5% error in scales that are based on force rather than the balance beam principle - and almost all electronic scales are currently based on force, since the load cell is a force measurement device.  Two corrections are provided:  the first is applied during calibration and the second is applied during use.  This system allows scales to be calibrated at one latitude and altitude and used at any other, without need of test weights, after the new coordinates are entered.  The correction is within 0.01% anywhere on the earth's surface.

Key benefits

The Auto-Cal advantage

Auto Cal is a shunt-calibration system that, when used with suitable Auto Cal load cells can eliminate test weights after the initial calibration.  Shunt calibration is a method of using a resistance in parallel with one arm of the load cell bridge to simulate a known load.  Once the scale is calibrated, the resistance is switched in and the reading recorded, for use in subsequent accuracy checks and recalibration.  When load cells are manufactured to tight tolerances they can be interchanged without need for recalibration, contributing further to the Auto Cal system.  Auto-Cal is optional on the 1X3-1945.

Specifications

Load cell excitation:4.5 volts, up to 4 - 350 ohm load cells
Load cell signal: 0.2 - 4.0 mV/V full scale
Compatibility:all scales listed in main menu
Resolution:15,000 displayed counts with less than 1/10 count RMS jitter
Reading speed:20 readings per second max (polled).  Up to 50 per second and streaming data available on special order
Filtering:Advanced 3-stage adjustable digital filter - extremely fast settling with good noise rejection
Output:USB "B" type connector, female, and 4-pin lockable Molex Micro-Fit connectors for both power and data
Load cell inputs:Four 8-pin lockable Molex Micro-Fit connectors
Power:5V DC +/- 0.25V  from USB connection or external to 4-pin Micro-Fit connector
Physical:steel case 5.5" x 2" x 1" or bare board.  Same mounting holes as for R1930/1932 below
Optional shunt calibration:Switchable shunt resistor creates reading to confirm calibration at power-up
Optional Virtual Serial Port (VCP):Allows the USB connection to appear as a serial RS232 port when using Windows

Model R1930/R1932 serial RS232 weight transmitter with Auto Cal

The model R1932 Auto Cal transmitter is a general purpose weight transmitter with RS232 output and inputs for up to four load cells.  Although intended for matched load cells of the Auto Cal type, the circuit board is also available with built-in summing for unmatched load cells.  This model is obsolete, replaced by the 1X3-1945 above.  However, it is still available on special order.

The R1932 has been optimized for fastest settling together with high rejection of vibration frequencies;  both parameters can be preset from a built-in menu.  Software can also be modified on a custom basis for different applications.

Key Benefits

Specifications

Load cell excitation:4.5 volts, up to 4 - 350 ohm load cells
Load cell signal: 0.2 - 4.0 mV/V full scale
Resolution:15,000 displayed counts with less than 1/5 count jitter
Filtering:Advanced 3-stage adjustable digital filter - extremely fast settling with good noise rejection
Output:9-pin RS232 connector
Power:12V DC (model R1932) or with wall adapter, 110/120V AC, 60 Hz, 5W. (model R1930)
Physical:steel case 6.5" x 5.5" x 1" or bare board

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