ABB Advant Controller 31 40 & 50 Series

General setup rules

An ABB AC 31 system always includes an AC 31 central unit. There are three types of central units:

- The 40 series central unit, with a local inputs / outputs extensions interface

- The 50 series central unit, with a local inputs / outputs extensions interface

and a CS 31 bus interface

- The 90 series central unit, with a CS 31 bus interface

Each central unit incorporates a specific number of binary inputs / outputs and occasionally

analog. It is possible, depending on the central unit, to increase the number of inputs / outputs,

to add input / output extensions connected directly to the central units or remote input / output

units via the CS 31 twisted pair.

Central units with extensions

The 40 and 50 series. It’s possible to increase the number of inputs / outputs of the basic

central unit by adding up to 6 local extension units of either type, binary or analog (Figure 1-1).

2.2. Central units with CS 31 bus

The 50 and 90 series. It’s possible to increase the number of inputs / outputs of the basic

central unit by adding remote units. The central unit controlling the system is called the

MASTER central unit. The maximum bus length is 500 m without an amplifier and 2000 m with

3 amplifiers (1 NCB or NCBR unit enables bus amplification for 500 m).

The master central unit can manage up to 31 connection points called SLAVES, such as:

- A remote unit with extension possibilities: a maximum of 6 extension units comprising of a

maximum of 8 analog input channels and 8 analog output channels

- A simple remote unit (without extension) with analog or binary inputs / outputs

- A remote TCAD display

- An ABB NCSA-01 variable speed drive interface

- A high speed counter unit

- A central unit (50 series with extension possibilities, 90 series and the previous 30 series)

- Or any other device which disposes of a CS 31 communication (see Figure 1-2).

Comment:

A slave fitted solely with binary channels occupies 1 connection point.

A slave fitted with binary and analog channels occupies 2 connection points of the available 31.

The maximum number of remote ANALOG units depends on the MASTER central unit:

- 50 series: - a maximum of 31 remote analog input units

- a maximum of 31 remote analog output units

- a maximum of 15 extensible remote units (ICMK14F1) with analog input / output

extensions + 1 remote analog input / output unit (15 x 2 + 1 = 31)

- or a mixed binary / analog configuration within the previous limits

- 90 series: - a maximum of 12 remote analog input units

- a maximum of 12 remote analog output units

- or a maximum of 12 slaves with analog extensions

Operation of the 40 and 50 series central units

3.1. Functional diagram

The 40 and 50 series central units memory is composed of two distinct areas:

- A SRAM memory where the user program and data is loaded.

- A Flash EPROM memory which contains:

- a backup of the user program with the program constants,

- the configuration data,

- and the system program protected against access from the user program.

An incorporated battery, which is available only in the 50 series, also enables the backup of

internal variables.

The user program is a set of universal functions conceived by the constructor to cover all

applications and ensure all the basic PLC functions. It is developed with the AC31GRAF

software. After being translated into instructions understable by the central unit it is loaded in

RUN or STOP mode into the SRAM and then saved from the SRAM to the Flash EPROM.

Thereby, at each program launch the user program, saved in the Flash EPROM, is copied to

the SRAM for processing by the microprocessor (Figure 1-3).

The structure of the system program memory, the user program, the inputs / outputs and

internal variables are described in the annex (mapping).

Program execution

The central unit microprocessor ensures the cyclic execution of the system as shown in

Figure 1-4.

The internal processing:

- PLC monitoring and control

- and processing requests from the terminal operator,

is executed in parallel with the previously described cycle.

The main program is processed sequentially. It may call up to a maximum of 12 sub-programs.

Each sub-program may be called numerous times in the main program.

Three types of interruptions may be executed parallel to the main program:

- A cyclic interruption

- A warning interruption triggered by an event on the I 62.03 input

- A warning interruption triggered by an event on the I 62.02 input

The interruptions have priority over the main program execution. If all three interruptions are

triggered simultaneously then the interruption triggered by I 62.03 has priority over the I 62.02

input interruption which in turn has priority over the cyclic interruption. Once an interruption has

been launched it cannot be interrupted by another (Figure 1-5).

The execution duration of a cycle (bus cycle + program cycle) is controlled by the central unit.

Any excess of the cycle time defined by the user in AC31GRAF is signaled by the ERR Led, at

the front of the central unit, as of the first program cycle.