Dametric
TVD-M2 / TVD-M3
TVD-M2-M3 EN.docx
May 26, 2011 / BL
3(8)
2.
DESCRIPTION
The TVD-M2/M3 monitors are used together with a vibration transducer to measure the touch point
vibrations in a pulp refiner.
The unit will work in the calibration mode or in the production mode. In the calibration mode the
unit has the highest sensitivity to detect the touch point without unnecessary plate wear.
In production mode, the unit will work with lower gain and will then work as a part in the plate clash
protection system. The modes are selected by an input logic signal.
The amplifier excites the transducer with a constant current. The transducer includes a built in signal
conditioner, and the signal output is superimposed on the feeding constant current. The transducer
signal is amplified, filtered and then monitored on both the front display and on the current signal
output.
The front display consists of a 20-segment led ramp and normally indicates the touch point signal
level.
The signal level is constantly compared with two adjustable alarm limit levels. The output is
deactivated when the signal level exceeds the limit level, which is adjustable by one turn
potentiometers.
If any of the limit push buttons is pressed, the corresponding alarm limit is displayed on the internal
led ramp and also monitored on the external analogue output.
The signal can be attenuated for production mode by a closing of an input. A single turn
potentiometer and a 4-pole dipswitch set attenuation and frequency response.
The signal can be attenuated for compensation of different transducer location, different type of
refiners and also the refiner main motor speed. A 4-pole dipswitch sets the attenuation.
The signal level is also amplified to a headset output. The headset is connected to a phono contact on
the top of the unit. The headset is used to listen to the actual touch point sound. The audible signal is
not affected by the dip-settings for transducer location or production gain.
The unit works together with four different type of transducers.
The VIM-T2 for touch point frequencies between 200Hz and 10kHz.
The TVD-T1 for touch point frequencies between 200Hz and 40kHz. This transducer is mounted on
the TDC-transducer and is normally used in the CD-refiners.
The TVD-T2 for touch point frequencies between 200Hz and 40kHz. The TVD-T2 is mounted on
one of the bolts for the plate holder.
The TVD-T2S has the same mounting method and frequency range as the VIM-T2 but has ten times
higher sensitivity. This transducer is normally used in the Conflo refiner.
There are two types of cables to be used between the unit and the transducers. The VIM-T2 uses the
cable K-VIMS25 while all other transducers use the cable K-TVDS25.
The TVD-M2 includes an AC/DC power unit, which converts and isolates the 115/230 VAC power
supply to the in12V and -12V DC-voltages.
The TVD-M3 is powered from a 24VDC source and includes a DC/DC converter for the internal
supplies.
