A Precision Digital Panel Meter For Weighing & Load Cell Applications Demanding Accurate Measurement.
Data Track has designed the Tracker 240 series of digital panel meters specifically for use with load cell transducers and as a panel meter for weighing applications.
All the Tracker 240 panel meters have a 5-digit display and transducer supply plus many software features including tare, zeroing, in-flight compensation, peak picking and extensive alarm functions.
As standard, the Tracker 240 panel meters are fitted with an analogue output and an RS422/485 2 or 4-wire communications interface to allow connection to data loggers, chart recorders, PLCs and computers. The 240 series have the same specification except that the Tracker 244 has 2 relay outputs to control external devices and the Tracker 245 has 4 TTL logic outputs. The displayed value can be in tonnes, litres, grams or any other engineering units.
6-Wire Ratiometric Input for maximum measurement precision.
Excitation is 10V DC (or optionally 20 volt DC for use with I.S. barriers) fully drift compensated by the ratiometric measurement technique.
It is possible to connect up to 4 x 300 Ohm load cells in parallel. More can be used if the resistance is higher (e.g. 8 x 700 Ohm load cells) and the total current does not exceed 120mA at 10V DC. An external 10V DC supply can be used, if required, still retaining the ratiometric measurement capability.
The user programmable analogue output allows the Tracker 240 panel meters to transmit the measured display value, the maximum, minimum or average value, or a value sent via the serial interface. The analogue output can be scaled for any portion of the display range and is configurable for 4-20mA, 0-20mA or 0-10 volt signals. Electrical isolation ensures that you avoid problems associated with earth loops.
Calibration Scaling and User Linearisation
Calibrating the Tracker 240 panel meters to load cells can be achieved in one of two ways. You can enter the values from the strain gauge manually in mV/V or the Tracker 240 can read the actual output from the transducer at 2 points in the range, normally at zero and another point near the maximum load that you want to measure. These measured values are stored with their associated display values as the calibration parameters. For non-linear signals you can independently calibrate the Tracker 240 panel meter (up to 8 points) to compensate for any non-linearity from the load cell.
The user can configure the Tracker 240 digital panel meter for the required engineering units and display resolution. The resolution is user configurable for 1, 2, 5 and 10 digits. This can be useful if a steady reading is difficult to achieve. Normally the full resolution would be displayed. For noisy signals, Data Track provides an independent display filter. You can select the display update rate to be 2, 4 or 10 per second and adjust the brightness to suit ambient lighting conditions.
Often plant vibration can affect the measured values and make the display appear "noisy". The Tracker 240 panel meter has a smart filter that samples the "noisy" signal from the load cells and then calculates a filter band value. When in use, the panel meter only applies the filter when the measured value rate of change is within the filter band. To allow a fast response for real change of signal, the panel meter turns the filter off until the signal rate of change is again within the filter band limits.
Status (Logic) Inputs
Data Track supply the Tracker 240 digital panel meters with two logic inputs to allow remote control of the
panel meter functions via switches or PLCs. Volt free contacts or open collector TTL outputs may activate the inputs.
You can individually program the 2 status inputs to perform one or more of the following functions.
Front Panel Function Buttons
2 front panel function buttons can be configured to give operator level access to one or more of the following functions:
Alarms can be flashed on the panel meter display along with the measured value.
You can individually configure the following parameters for each of the 4 alarm menus:
The Tracker 240 digital panel meters are equipped with an isolated RS422/485 serial communications interface (optionally RS232) to allow connection to computers or PLCs. Data Track supports four protocols including Modbus RTU and Datatrack's ASCII protocols to allow easy integration with most SCADA packages.
You can also select Master Mode to allow digital transmission to a remote display or printer. The combination of a Tracker 240 panel meter and an HMI, fitted with a Modbus compatible RS485 interface, becomes a powerful stand-alone batch control and recipe selection system. You are able to tailor the HMI's display and function buttons for any application and language. Many HMI units can also be a gateway for Fieldbus connection (e.g. Profibus, Device Net). A single HMI can communicate with up to 32 Tracker 240 panel meters.
Universal Power Input
Wide-ranging 90-265V AC input allows world-wide installation. A low voltage 24V AC/DC supply option is available.
Download the related product documentation using the links at the top of this page or contact us to discuss your requirements further.