In case of a difference, the safety relay is switched of and an error is generated.
The safety controller also reads and processes the values of the keyboard.
5.1.4 Signal processing circuits.
/ The signal processing and stimulation circuits are identical for channel A and channel B. Only the
circuits for channel A are explained.
The signal processing circuits are built around U11 (CH A). This IC is a programmable sinusoidal
generator, producing a sinusoidal signal of a determined frequency. The form of the amplitude is
determined by DAC U24 and U14.
Depending on the type of current the therapist has chosen, the multiplexing IC U34 (CHA) will select
the right input and connect it to the amplifier circuits (Pow A):
X0: sinusoidal signal sometimes modulated in amplitude (depending on current waveform).
X1: fixed voltage.
X2: DAC_A: amplitude modulated signal for diadynamic currents (without sinusoidal component).
X3: inverted signal of X0.
5.1.5 Stimulation circuits.
After the amplitude and/or the waveform of the signal are generated the stimulation circuit amplifies
it, turns it into a CC or CV signal and if necessary changes the polarity and/or rectifies the signal.
Basically there are four possible hardware configurations, and the amplifier circuit can be redrawn
according to each configuration.
Configuration 1: mode CC, pulsed (tens, rectangle, triangle, diadynamic).
Configuration 2: mode CC, continuous (interference, direct continuous).
Configuration 3: mode CV, pulsed (tens, rectangle, triangle, diadynamic).
Configuration 4: mode CV, continuous (interference, direct continuous).
Phyaction Guidance E/C – service manual version 0.5 Page 17
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