Hardware Manual

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

Saia-Burgess Controls AG

Expansion housings and bus cables

CPUs and expansion housings

3

3.6 Expansion housings and bus cables

The PCD2.M120/M150/M170/M480 can be expanded with PCD2, PCD3 or PCD4

components, and additional module sockets are provided:

Type M120/M150 M170 M480

Maximum number of inputs/outputs or

I/O module sockets for the system:

When PCD2 components used exclusively 255 1)2)

16

When expanded with PCD3 components 255 1)2)

16

510 1)2)

32

1023 1)2)

64

When expanded with PCD4 components 255 2)3)

16

1) Using digital I/O modules PCD2/3.E16x or A46x with 16 I/Os each

2) On all PCD2s, address 256 is reserved for the watchdog; on the M170, address 511 is also reserved for this

purpose. The I/Os reserved for the watchdog cannot be used by the user, and no analogue or H modules may be

attached to sockets with base address 240 (and on the M170, 496 also)

3) Not all PCD4 I/O modules are suitable for use with PCD2 CPUs; please refer to the section on “Expansion with

PCD4 components”