For electrical checks power the signal conditioning amplifier as explained in the user manual for the device. For TTS amplifier the table below gives the readings that you should expect in a normal situation for a no load condition
LOAD CELL SUPPLY AND OUTPUT SIGNAL | |
EXC + to EXC | 10V DC |
EXC+ to SIG + or EXC+ to SIG - | 5V DC |
EXC - to SIG + or EXC – to SIG - | 5V DC |
SIG+ to SIG- | Between ± 10mV |
In a no load condition voltage readings across SIG+ and SIG – will be the dead weight of the roller. As a rule of thumb these should be no greater than 50% of the load cell range. In an ideal installation these voltages will be similar. Note the voltage at no load including the polarity.
Deflecting the sensing roll should increase the difference between SIG+ to SIG- equally if the roller is deflected in the centre of the sensing roll. For full scale load this value should increase positively by more than 3mV between zero load and full scale load.
For example
No load = -1mV, Full scale load = +5mV, Difference is 4mV positive going
The voltage should return quickly to their ‘zero’ position once the load is removed. Check each cell in turn.
If these do not return to zero then you should check that the mechanical arrangements are not impeding this.
If the voltage appears to drift then in the first instance check for misalignment or mechanical coupling errors.
