AB 1794-IE8 FLEX I/O Analog Modules

AB 1794-IE8 FLEX I/O Analog Modules

Manual Overview and the FLEX I/O System

Manual Content and Purpose: Designed to guide the user through the use of the FLEX I/O analogue modules, covering installation, programming, and troubleshooting, this manual is intended for users who are able to operate Allen-Bradley programmable controllers and understand block transfer programming. The manual describes the FLEX I/O system components and the types of analogue modules that work together through adapters, terminal blocks and I/O modules, which are available in a variety of types to suit different applications.

The FLEX I/O system consists of adapters, terminal blocks and I/O modules. Adapters provide internal logic power for multiple I/O modules; terminal blocks are used for wiring two- or three-wire devices; and I/O modules contain bus interfaces and circuits to perform specific functions.

Analogue Module Installation

Prepare for installation: Calculate the power requirements of each module and ensure that the total current does not exceed 10A, otherwise a separate power supply is required. Confirm that the product complies with the EU directive, pay attention to static electricity protection during installation, and avoid removing or replacing the terminal blocks under charged conditions.

Installation steps: Installation includes mounting the terminal block (DIN rail or panel/wall mounting available), mounting the analogue module to the terminal block (note the key switch position and the Flexbus connector status), and connecting the wiring (wiring varies between modules and terminal blocks). Once the module is mounted, the green power indicator shows whether the module is powered on or not.

Module Programming: The module communicates with the processor via a bi-directional block transfer. Configuration Block Transfer Write (BTW) is used to set up the module functions and Block Transfer Read (BTR) is used to get the module information. The manual gives programming examples for the PLC-3, PLC-5 and PLC-2 processors, emphasising the need to pay attention to the order in which the modules are powered up, the creation of data files and the monitoring of status bits. The analogue data format is 12-bit resolution, left-justified to a 16-bit field, with the highest bit being a sign bit.

Module Configuration and Data Reading

Configuration method: When using the Remote I/O Adapter, module functions such as input/output range selection, safety status value selection, etc. are configured via block transfer write commands. The input channels can be configured with various voltage or current ranges and the output modules can be set with safety status values.

Data reading: Transfer module status and data to processor data table through block transfer read command. Read/write words and bit/word descriptions are different for different modules, which need to be operated according to specific modules.

DeviceNet Communication and Mapping

Communication structure: The DeviceNet Manager software is used to configure the FLEX I/O DeviceNet adapter and related modules. In the polled I/O structure, output data is received in module order, and input data is received first in the adapter status word and then in module order.

Data Mapping and Default Values: It introduces the data mapping methods of different analogue modules in DeviceNet, as well as the default values and real-time size settings of the modules. The default values are assigned by the adapter when the system is first powered up and there are no previous stored settings, and the I/O data size can be adjusted according to the requirements.