Lloyd LS1 - Converting an Encoder Extensometer; Extensometer Verification; PC Diagnostic Mode

LS SERIES SERVICE MANUAL
ISSUE 4.0 DIAGNOSTIC MODES 4
11.6 Converting an Encoder Extensometer
A +5V supply is available on terminal T14 on the 04/1408 Extensometer PCB and the ground is
available on terminal T7.
If a single encoder is used, the encoder outputs are connected to terminals T10 and T11 on the
PCB. If two encoders are used, to give a differential extension, the second encoder output is
connected to terminals T12 and T13 on the PCB
The extensometer bit scale is the encoder resolution in mm and if it is not known, it can be
calculated by moving the extensometer a known distance.
11.7 Extensometer Verification
It is recommended that each extensometer is VERIFIED (checked) for accuracy at yearly
intervals. The verification procedure involves either moving the extensometer arms by a known
distance (contacting extensometer) or by moving a reflective target by a known distance (non
contacting extensometer) then checking that the extension displayed on the console LCD is
within the required accuracy (usually 0.5% or 1%).
If the displayed extension readings are found to be within the required accuracy then no further
action is required. However, if the extensometer does NOT achieve the required accuracy, then
it has to be CALIBRATED by entering calibration points.
Note that an extensometer can ONLY be Verified if an accurate means of measuring
extension is available. For small extensions, say up to 25mm, slip gauges, a calibrated
micrometer or a calibrated vernier can be used and for extensions above this value a
calibrated engineers rule may be used.
11.8 PC Diagnostic Mode
This mode is used to read the voltages fed to the 16 way multiplexer.
Note that a resistor chain halves the +15V and -15V power supplies before being fed to the
multiplexer so these voltages will be displayed as approx. +7V5 and -7V5.
1 Switch the Machine On.
2 Connect the USB cable to the PC and to the USB socket of the machine.
3 Start Windows Hyperterminal and set the Baud Rate to 57,600 with 8 Data Bits, 1 Stop Bit
and No Parity.
4 Type the word test on the Hyperterminal screen.