Figure Q1 shows the schematic diagram of a sheet thickness control system. The system uses a linear variable differential transformer (LVDT) as the thickness measuring means and an error detector. The AC error from the LVDT is converted to a DC error by the discriminator (a discriminator is an AC-to-DC converter whose output magnitude varies linearly with the input magnitude, and whose output sign depends on the relative phase of the input).
Please draw a block diagram for the sheet thickness control system. NOTE: the time delay can be represented by a time delay block at the suitable location of your block diagram.
Amplifier
Discriminator (AC-to-DC converter) AC-DC error signal
DC motor
Gear reducer
Linear variable differential transformer (LVDT)
Controlled roll
Sheet
Sheet velocity
Fixed roll
Time delay