Pilz PSSu E S ABS SSI - Manual (Page 18)

4.1 Module features
4 Function description
Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, 73760 Ostfildern, Germany
Telephone: +49 711 3409-0, Telefax: +49 711 3409-133, E-Mail: [email protected]
4-2
Timing diagram: Example of SSI data transfer:
Key:
The bit width in the example is 6. The position of the encoder is 001101
in gray code, i.e. 9
D
.
 a: Data transfer begins with a falling edge at the Cl signal.
 b: The first bit is transmitted with the first rising edge from the Cl sig-
nal.
 c: The time up to the second rising edge is the period length T. 1/T is
the signal frequency.
 d: The last rising edge from the Cl signal ends the transfer. The en-
coder acknowledges the end of the transfer with a 0 signal.
 e: The encoder can transfer data again as soon as there is a 1 signal
at input D.
4.1.2 Integrated protection mechanisms
Integrated protection mechanisms 4- ][Schutzmechanismen E/A-Module
When the PSSu E F PS1(-T) is used to supply the system, the module
supply is buffered for 20 ms if the supply voltage is interrupted.
][Schutzmechanismen ST-Module
The module detects the following errors:
 Start-up error
 Configuration error
 ST communication error
 Bus termination error
Cl
D
a b d e c