Hardware Manual

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

Saia-Burgess Controls AG

Planning an application with PCD1/2/3 components

Guidance

2

2.2 Planning an application with PCD1/2/3 components

The following aspects should be considered when planning PCD1/2 applications:

● The internal load current taken by the I/O modules from the +5 V and V+ supply

must not exceed the maximum supply current specified for the CPUs

● The CPU type determines the maximum number of modules

● The total length of the I/O bus is limited by technical factors; the shorter, the better

When planning an application, we recommend the following procedure:

^ Select the I/O modules according to requirements.^

^ Check that the number of modules is allowed:

PCD

Type

Max. number of I/O modules Max. number ¹) of digital I/Os

PCD1/

PCD

CPU

PCD

expan-

sion

PCD

expan-

sion

Total PCD1/

PCD

CPU

Expan-

sion

Total

PCD1 4 – – 4 64 – 64

PCD2.M120/150 8 8 8 16 128 128 (-1) 256 (-1)

PCD2.M170 8 8 24 32 128 384 (-2) 512 (-2)

PCD2.M480 8 8 56 64 128 896 (-1) 1024 (-1)

¹) PCD2 modules and PCD3 modules with 16 I/Os each

The values in brackets have to be subtracted from the maximum number of digital

I/Os because of the watchdog relay.

If you want to expand PCD2 CPUs with PCD3 LIOs/RIOs, please refer to the

planning instructions in the PCD3 manual.

If the number of modules is allowed, continue from ; if not, select a different CPU

^ If necessary, select the PCD2 expansion housing:

● PCD2.C100 with 8 module sockets

● PCD2.C150 with 4 module sockets

● PCD2.K100 26-core extension cable for connecting PCD2 base units

mounted beneath each other.

● PCD2.K110 26-core extension cable for connecting PCD2 base units

mounted side-by-side.

● PCD2.K120 26-core extension cable for specific applications (length 2 m).

● PCD2.K106 26-core extension cable for connecting PCD2 CPUs with

PCD3 module holders.

^ Where PCD2.Wxxx and PCD2.Hxxx modules are used, calculate the load

current from the internal +5 V and V+ supply (use the worst-case / highest

values)