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Specialized ADC module for connecting up to 8 strain gauges with a resistance from 100 Ohms to 1 kOhm (for sensors of 50 Ohm see the note below).
Up to 8 channels of sigma-delta ADC bridge imbalance measurement, 24 bits, with software-switchable millivoltage measurement subbands, analog input low-frequency filters and additional digital filtering with ADSP-2185M.
The source of the reference voltage (for supplying strain gages) with software-switchable output voltage +2.5 V or +5 V (constant or alternating) and total operating current load up to 400 m.
Built-in compensating DAC for each ADC channel for software-controlled hardware compensation of the initial unbalance of strain gages without reducing the dynamic range of the ADC.
The internal circuits of the extension to the full bridge when connected to external half-bridge or (for LTR212M-1) when connected to standard quarter-bridge sensors 200 or 350 Ohms. User has an opportunity to mount his own additional resistors to the removable submodule for LTR212M-1 with non-standard resistance of the external quarter-bridge sensor.
Note: It is possible to connect up to 8 strain gauges of 50 Ohm with a supply voltage of +2.5 V, or connect up to 4 strain gauges of 50 Ohm with a supply voltage of +5 V, but only in conjunction with LTR212, LTR212M-2 or LTR212M-3).
|Number of channels||4/8|
|Resolution||24 bits, sigma-delta ADC|
|Input signal measuring subranges||±80 mV, ±40 mV, ±20 mV, ±10 mV,
0…80 mV, 0…40 mV, 0…20 mV, 0…10 mV
|Input impedance||Not less than 10 MOhm|
Limits of the permissible basic relative error, in percents, without the use of "Calibration of zero" operation.
Notation in formulas: XК is the final value of the set measurement subband, V; X - the value by LTR212M, V
|The range of common-mode voltages at the measuring inputs (to "AIN +" and "AIN-") relative to the supply point of the bridge "-EXC"||
|The coefficient of suppression of input common-mode interference when the unbalance of external input circuits resistances is equal to 1 kOhm||Not less than 100 dB|
|Reference voltage source (RVS)|
|Output voltage of RVS (sensor supply voltage)||(2.5 ± 0.1) V or (5 ± 0.2) V, the DC voltage or alternating current (programmable)|
|Maximum total load current||400 mA|
|Amplitude-frequency characteristics and parameters of the built-in digital filtering|
|Maximum sampling rate (for four-channel mode)||7600 Hz for each channel|
|Stability of the conversion frequency of one module (in new versions of LTR212M, the ADC conversion frequency is synchronized with the frequency of the LTR crate reference oscillator)||±50 ppm|
|Bandwidth of the signal transmission at -3 dB level with digital filtering disabled||2000 Hz|
|Digital tunable low-pass filter||
See the main features of LTR modules
|Differences between modifications|
Note: L-CARD recommends to switch from LTR212 to LTR212M-1, LTR212M-2, LTR212M-3 in new projects.
Hardware description, assignment and connection of signals is given in the User's Guide.
|connection of up to 4 quarter-bridges, 4 half-bridges and 4/8 full bridges, 0.5 MB Flash memory, calibration for reference voltage source 2.5 V and 5 V|
|connection of up to 4 half-bridges and 4/8 full bridges, 0.5 MB Flash memory, calibration for reference voltage source 2.5 V and 5 V|
|connection of up to 4 half-bridges and 4/8 full bridges, 256 bytes EEPROM, calibration for reference voltage source 5 V|
LTR212 module. Programmer's Guide.
Ltrapi basic library. Programmer's Guide.
Description of the software for Windows, Linux, FreeBSD and QNX.
LTR modular DAQ system. User's Guide (revision 3.1.0).
Starting to work with DAQ system LTR. Questions about the software.
LGraph2 is a free multi-channel data recorder for Windows. Version 2.35.20 provides the possibility of simultaneous data visualization and recording from the ADCs: L-502, L-780M, L-783, L-791, E-502, E14-140, E14-140M, E14-440, E-154, E20-10, LTR11, LTR114, LTR27, LTR212, LTR216, LTR22, LTR24, LTR25, LTR51. It requires an updated version of the LComp driver (from version 01.04.2010) and ltrserver (no lower than 18.104.22.168).
OPC DA Server for L Card data acquisition modules and LTR crate system. Version 1.0.10.
Beta version. LCOMP library for Windows XP/Vista/Win7/Win8/Win10 32 and 64-bit versions with drivers. The installer and drivers are digitally signed. The library is built on the basis of modern WDM-drivers rewritten on WDF. It includes the WDM driver itself for L-CARD hardware, the DLL library with source code, programming examples, electronic description, etc. The LCOMP library provides support for almost the entire range of products: PCI boards, USB modules. ISA support is excluded.
The library includes “L-Graph I” software. L-Graph I supports the following devices: L-1450, L-761, L-780, L-783, L-791, E14-140, E-154 and E14-440. Files recorded by L-Graph I can also be read and processed using the demo-version of PowerGraph v.3.X.
The ltrd service. Version 22.214.171.124. Provides communication with LTR crates. It is a replacement for the LTRserver software while maintaining the compatibility of the program interface. ltrd is designed for the same purpose as LTRserver, but it is a service that runs when the system is started. The graphical interface to the service is provided by a separate LTR Manager program.
Attention! Only one of the programs ltrd or LTRserver can work at a time.
Libraries for working with LTR crates and modules. Version 1.32.22.
LTR Manager software. Version 1.5.2. Graphical interface to the ltrd service. Provides an interface similar to the LTRserver interface when working through the ltrd service.