LS SERIES SERVICE MANUAL
ISSUE 4.0 OVERVIEW 4
The machine measures two parameters during the sample test mode. These are the load
applied to the test sample, by moving the crosshead, together with the crosshead movement
during the test.
The load is measured using either a YLC loadcell or an earlier XLC loadcell. The YLC loadcell is
fitted with an eye end arrangement similar to the lower eye end design fitted to the frame. The
YLC loadcell also has an improved amplifier with lower noise than the XLC loadcell. Therefore,
it is recommended that a YLC loadcell is used with these machines. However, an XLC
loadcell can also be used, noting that the lower limit of verification may be higher (due to slightly
increased noise) and the vertical position of the grips will alter if the grips are rotated.
The load signal is analogue and is converted into data using a 16 Bit ADC (effectively
increased to 18 Bit by the embedded code) but the extension signal is digital. Both types of
signal are measured at 1000 Hertz so the load and extension values are available at a data rate
of 1000 readings per second.
If a single Analogue External Extensometer is used, the load and extension analogue voltages
are multiplexed before being converted so the load data rate and the extensometer data rate are
both 500 readings a second. The digital encoder is still read at the normal speed of 1000
readings per second. Note that the signal from an Analogue External Extensometer is converted
into data using a 16 Bit ADC.
If a single Digital External Extensometer is used, the encoder and extensometer digital signals
are sequentially measured so the encoder data rate and the extensometer data rate are both
500 readings a second. The load is still read at the normal speed of 1000 readings per second.
The frame and covers are designed for ease of maintenance. Removing the lower cover gives
access to the mains input module, power supply, transformer, PCBs, limit switches, safe-line
circuits and the drive belt. To gain access to the motor, the rear backplate and motor cover may
also have to be removed.
1.3 Full Control Console
The Full Control Console contains a 4 line by 40-character backlit alphanumeric LCD display, a
large membrane keypad and a buzzer. The LCD contrast is adjusted by the potentiometer on
the console PCB.
The text on the LCD display can be displayed in one of various languages and the required
language is selected using the EDIT, GLOBAL, >, CURRENT LANGUAGE option.
The console allows positioning of the crosshead using the slow/fast - up/down jog keys and the
return key. The current load and extension values can be zeroed (using the Ø key) and a test
can be started (using the ► key) or stopped/aborted (using the ■ key). Note that a NEXYGEN
Plus 3 test can also be started by using the start button if this feature is selected in the software.
The console displays the current load and extension values in various units and these are
selected using the EDIT, SETUP, TEST RESULTS, RESULT UNITS option.
The Full Control Console also enables a test to be defined and performed without using a
computer, i.e. the machine can be used "Stand-Alone".
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