Hardware Manual

Hardware Manual PCD 1 / PCD 2 Series│Document 26 / 737│Edition EN 15│2008-07-22

Saia-Burgess Controls AG

PCD2.H150

Input/output (I/O) modules

5

5.16.1 PCD2.H150, SSI interface module for absolute encoder

Application

The PCD2.H150 Module is an interface module for the SSI standard. (SSI =

Synchronous Serial Interface). The SSI standard is used with most absolute

encoders. Details of SSI specifications can be obtained from the STEGMANN

company’s brochure: “SSI-Technical Information”.

The hardware consists of an RS 422 port for the SSI interface and 4 general-purpose

digital outputs. Functionality is provided by an FPGA (field programmable gate array).

Technical data

Resolution: configurable for 8 ... 29 data bits and 0 ... 2 control bits

Clock frequency: configurable for 100 kHz, 200 kHz, 300 kHz

and 500 kHz (input filter designed for 500 kHz)

Frequency has to be selected

depending on cable length:

Cable length Frequency

< 50 m max. 500 kHz

< 100 m max. 300 kHz

< 200 m max. 200 kHz

< 400 m max. 100 kHz

Data code: configurable - Gray or binary

Read mode: Normal (single read). Ring mode: ‘double read and com-

pare’ (not all encoders support this function)

Offset position: An offset can be defined when initializing the PCD2.H150.

The defined offset is always subtracted in the FBs. The

‘Set Zero’ command also uses this offset register.

Execution time: typically 1.5 ms for reading the SSI value

Cable break detection: detected with the FB ‘timeout’ (10 ms)

Flags ‘fTimeout’, (for cable break, encoder fault or incorrect

addressing)

‘fPar_Err’, (if an incorrect FB parameter is sent)

‘fRing_err’ (if compare error in ‘double read’)

SSI interface

1 input for SSI data RS 422, electrically isolated

1 output for SSI clock RS 422, electrically connected,

as the encoder input is normally isolated

Digital outputs

Number of outputs:

Terminal 4 = A12:

Terminal 5 = A13:

Terminal 6 = A14:

Terminal 7 = A15:

4

Speed high

Speed low

Dir + positive direction

Dir - negative directiondirection

Switching capacity: 0.5 A each in the range 10 ... 32 VDC, residual ripple max.

10 %

Short circuit protection: yes, Imax=1.5 A

Electrical isolation: no

Voltage drop: max. 0.3 V at 0.5 A

Circuit type: positive switching

Output delay: typically 50 μs, max. 100 μs, ohmic load

Power supply

Internal current consumption:

(from +5 V bus)from +5 V bus)

25 mA

Internal current consumption:

(from V+ bus)

0 mA