To Next Page

To Previous Page

Saia-Burgess Controls AG

Hardware manual for PCD3 series │ Document 26-789 ENG19│ 2018-06-29

Connections on orange terminal block

PCD3.Mxxx0 Classic CPU and expansion enclosure

3-39

3.15.2 Interrupt inputs

5540

Saia PCD3.M

Saia PCD3Saia PCD3

Terminal 3 and 4 for interrupts inputs Int0 and Int1

Basics

The digital input modules are not suitable for immediate reaction to events or fast

countingbecauseoftheinputltersandtheinuenceofthecycletimeoftheuser

program. Most CPUs have 24 VDC interrupt inputs for this purpose.

Two interrupt inputs are located on the main PCB and can be connected via the

8-pin, pluggable terminal block (terminals 3 and 4). Source operation is used.

Interrupt

inputs

Called XOB on

positive edge

Plug

terminal

Direct input query

Base and

standard CPU

Power CPU

PCD3.Mxx60

INT0 XOB 20 3 I 8100 ---*

INT1 XOB 21 4 I 8101 ---*

*availableviamediamappinginthedevicecongurator

An associated XOB is called (e.g. XOB 20) on a positive edge on the interrupt

input. The code in this XOB determines how the event responds, e.g. by

incrementing a counter.

The code in XOBs, which are called by interrupt inputs, must be kept as short as

possiblesothatsu󰀩cienttimeremainsbetweentheinterruptstoprocesstherest

of the user program.

Many FBoxes are intended for cyclic calling and are therefore not or only partially

suitable for use in XOBs.

Exception: The FBoxes of the Graftec family (standard library) are well suited.

SBC PCD3 Series User Manual

Questions and Answers: