Siemens AS-i SlimLine Diagnostic Guidelines

Engineering selection and fault diagnosis of Siemens AS-i SlimLine Compact module

In industrial fieldbus applications, AS Interface (AS-i) is widely used to connect sensors and actuators due to its advantages of simple wiring and low cost. However, as the control cabinet space becomes increasingly tight, higher requirements have been put forward for the width and functional integration of I/O modules. The Siemens SlimLine Compact series (3RK1/3RK2) is designed for this purpose: its digital, ASIsafe, and analog module widths are only 17.5mm or 22.5mm, and it achieves fast loops for AS-i and auxiliary power Uaux through optional device connectors. This article provides a detailed overview of the mechanical installation, electrical wiring, addressing configuration, core parameters of various types of SlimLine Compact modules, as well as LED based fault diagnosis methods from an engineering practical perspective, to help on-site engineers quickly locate problems during debugging and maintenance.

Product series and selection points

SlimLine Compact modules are divided into three categories based on their functions: digital I/O modules, ASIsafe modules, and analog modules. Its most prominent advantages are width reduction and flexible switching of sensor power supply.

1.1 Digital quantity module

The digital module covers multiple types of slave stations:

Pure input module: 4DI, supports 2-wire or 3-wire sensors. The 2-wire sensor version (such as 3RK2200-0Cx00) has a width of only 17.5mm and is powered by AS-i; The 3-wire sensor version (3RK2200-2Cx00) has a width of 22.5mm and can be powered by AS-i or Uaux through the back dial switch.

Input+output module: 4DI/4DQ (transistor output) or 4DI/4RQ (relay output), with a width of 22.5mm. The output current capability is 2A (PNP), and the relay contacts can be either normally open or conversion type.

Pure output module: 4DQ transistor output (such as 3RK2100-1Cx00), width 22.5mm.

Attention should be paid when selecting: if a 2A or above drive or AC load is required, a relay output type must be selected; For high-speed switch applications (PWM or frequent action), transistor output is more suitable.

1.2 ASIsafe module

The safety module is used to connect mechanical contacts such as emergency stop buttons and safety door switches, and complies with ISO 13849-1. Provide two models:

2F-DI (such as 3RK1205-0Bx00): Two fail safe inputs with a width of only 17.5mm. Designed specifically for mechanical contacts and not suitable for semiconductor output sensors.

2F-DI/2DQ (such as 3RK1405-2Bx00): Two fail safe inputs+two standard PNP outputs, with a width of 17.5mm. The standard output can be powered by AS-i or Uaux and selected through a dip switch.

The safety module does not occupy additional safety relays and communicates directly with the safety master station through the AS-i Safety protocol, achieving SIL2/PL level d.

1.3 Analog module

The analog module is divided into three categories, with an average width of 22.5mm:

4AI voltage/current switchable (3RK1207-0Cx00): Four analog inputs can be selected through DIP switches for ± 10V, 0-20mA, and 4-20mA, respectively. Priority should be given to using Uaux for sensor power supply (if connected), otherwise it will automatically be taken from AS-i (total current ≤ 46mA, otherwise Uaux needs to be connected).

4AI Pt100/Ni100/resistor (3RK1207-3Cx00): Used for measuring thermal resistors (Pt100, Ni100) or 0-600 Ω resistors, supporting 2/3/4 wire connections.

2AO voltage/current switchable (3RK1107-0Bx00): Two analog outputs that can be switched to ± 10V, 0~10V, 1~5V, 0~20mA, 4~20mA, or ± 20mA. The output has short-circuit protection and no-load protection.

The parameters of the analog module (filtering frequency, smoothing filter, range) are configured through the AS-i master station parameter bits (P3-P0), and the specific correspondence is described in Chapter 9 of the manual.

Mechanical installation and use of equipment connectors

SlimLine Compact supports two installation methods: standard 35mm DIN rail and wall mounting. Among them, device connectors can greatly simplify the wiring of AS-i and Uaux.

2.1 Rail Installation (Direct Installation)

Insert the upper part of the module back into the upper edge of the guide rail, and then press the lower half until you hear a "click" sound. When disassembling, first unplug the terminal, press the module down with a screwdriver, pull out the lower half, and then lift it up.

2.2 Equipment connector installation (recommended for parallel connection of multiple modules)

There are two types of device connectors: regular connectors (3RK1901-1YA00 is 17.5mm wide, 3RK1901-1YA10 is 22.5mm wide) and terminal connectors (with left cover, 3RK1901-1YA01/1YA11). The usage steps are as follows:

Insert the connector onto the guide rail and push it side by side until it clicks into place.

Install a terminal connector (with cover plate) at the far left end of the link.

Insert each module directly into the corresponding connector, and AS-i and Uaux will be automatically connected in series to each module through the internal busbar of the connector, without the need for additional wiring.