CT-EW1: Step Calibration Table
Supplied By: Lennartz Electronic, Germany
The CT-EW1: Step Calibration Table
Designed and endorsed by Erhard Wielandt (Institute of Geophysics, Stuttgart University) whose reputation in the field of broadband seismometry is second to none, the CT-EW1 combines mechanical precision with portability and ease of use.
The CT-EW1 is powered by a standard 9V battery (LR22 / 6LR61) located inside the hand held control box. Operation is truly push button style.
The relatively simple looks of the instrument are deceiving, though; a carefully thought out and painstakingly machined mechanism makes sure that the table performs an up-down motion only, with no undesirable amount of tilt- or torque-like motion getting in the way. Since seeing is believing we have added not one, but two high-precision dial gauges (1 μm precision) on opposite table edges so that you can control the precise amount of displacement. Nothing could be more intuitive and more direct. No software involved, no “magic number” conversion factors - just read the amount of displacement off a circular dial.
It is easy to see how the table works for the vertical component. Conventional shake tables have to be tilted 90° for excitation of the horizontal components. CT-EW1 doesn’t work that way (it isn’t a shake table either). Instead, an extension “bridge” is placed on the table, thus translating the up/down motion of the table top into a stepwise tilt excitation of the horizontal components as shown in the sketch.
Technical details for CT-EW1 Step Calibration Table
|Technical Data for CT-EW1 Step Calibration Table|
|Instrument type:||Vertical Single-Step Displacement Actuator|
|Actuator type:||DC Motor with two-speed gearbox and switch-activated center stop|
|Power supply:||9V battery (LR22 / 6LR61)|
|Operation:||Handheld Control Box (push button, switch)|
|Dimensions (table without bridge):||250 x 250 x 150 mm|
|Dimensions (extension bridge plus pedestal):||215 x 405 x 150 mm|
|Dimensions of Table Top:||215x195 mm|
|Weight (table without bridge):||4.7 Kg|
|Weight (extension bridge):||2.4 Kg|
|Payload:||Designed for sensors in the STS-1/ STS-2 / CMG-3 class|
|Amount of displacement:||approx. 0.8 mm / 0.2 mm (high/low gear)-(exact amount shown on two independent mechanical dial gauges)|