Analog Devices 6B Series Signal Conditioning Overview

The 6B Series delivers sensor-to-host signal-conditioning for remote applications. Software-configurable for a wide variety of sensor types, including: analog input, analog output, and digital I/0, the 6B Series is intended for remote data acquisition, machine monitoring, remote energy management and process monitoring and control applications. Including transformer-based isolation, ranging, linearization, A/D conversion and RS-232C/RS-485 serial communication for up to 256 channels per serial port, the 6B Series modules and boards are a complete, low-cost interface between computers and analog signals. All 6B Series input/output modules are fully encapsulated and identical in pin-out and size, facilitating their ability to be mixed and matched with all other 6B Series modules on the same backplane. The 6B Series is fully rated over the industrial temperature range of -25°C to +85°C.

Applications

Process Monitoring & Control

Test Stand Automation

Machine Monitoring

Material Testing

Remote Energy Management

Laboratory Data Acquisition

Each 6B Series module and board is a complete microcontroller­based process monitoring and control system, with all calibration, address and linearizing parameters stored in non-volatile memory. Being microcontroller-based, 6B Series modules can be configured for various sensor types, including RTD and thermocouple, and a wide variety of input ranges. This reduces the number of different modules that need to be used in a given application and carried in inventory. By distributing the processing needs down to each individual node, the host is off-loaded for supervisory and higher-level control functions.

Designed for industrial applications, the 6B Series modules incorporate transformer-based isolation with surface-mount manufacturing technology ­ providing increased reliability at low cost. The compact, rugged 6B Series analog modules can be mixed and matched on a 16-channel backplane for high density, remote process monitoring and control.

Communications between backplanes, modules and host is in ASCII over an RS-232C link or RS-485 bi-directional serial bus. Circuitry to convert RS-232C to RS-485 is built into the 6B backplane. Baud rates are software programmable, with speeds up to 19.2 KBaud.

Similar to analog I/0 modules, the 6B Series digital I/0 subsystem, Model 6B50, also has an on-board microprocessor and nonvolatile memory. All digital channels are addressable on a per-byte or per-bit basis.

The 6B Series digital subsystem communication is compatible with the overall 6B Series communication protocol. Each digital I/O board can be configured for its address, baud rate and checksum status. Connection to the 16- and 24-channel solid state relay backplanes is by a 50-conductor ribbon cable. This enables interfacing with inputs and outputs from 4 V to 240 V. Power control modules are also available that can switch up to 3 A and come with a variety of ratings for low voltage DC up to 280 V AC.

The 6B Series input modules accept signals from thermocouples, RTD's, millivolt, voltage, and process current signals. Each analog input signal is conditioned and scaled by a programmable - gain amplifier and digitized by a 16 - bit integrating converter under microprocessor control. The digitized value is passed serially across a magnetically-isolated barrier (1500 V rms for Models 6B11, 6B12, 6B13; 2500 V rms for Models 6B11HV, 6B12HV, 6B13HV) and clocked in by a custom controller chip. The on-board microprocessor then converts the data into engineering units as determined by the channel parameters. In between conversions, the microprocessor auto-zeros the offset and gain by monitoring the on-board temperature and compensating for reference drift. Cold junction compensation (CJC) is also performed at this stage. The modules use these compensation factors to ensure the highest accuracy possible.

The 6B11 and 6B11HV linearize and compensate J, K, T, E, R, S and B thermocouples. These modules also digitize millivolt and voltage ranges from ±15 mV to ±5 V as well as process current inputs, 0 mA to 20 mA. The 6B12 and 6B12HV accept millivolt inputs from ±150 to ±500mV, voltage inputs from ±1 to ±50 V, and process current inputs. The 6B13 and 6B13HV linearize platinum, nickel, and copper RTDs. All modules return data in engineering units, or as a percentage of full scale range.

Software utilities included with the 6B Series User's Manual are used to configure the 6B11, 6B11HV, 6B12, 6B12HV, 6B13 and 6B13HV modules for address, input range, baud rate, data format, checksum status, and integration time. All programmable parameters are stored in the non-volatile memory of the module.

The 6B21 analog output module provides digitally-controlled, isolated current loop output at a resolution of 12 bits. Output range is selectable to either 0 to 20 mA or 4 to 20 mA.

Software is used to configure the 6B21 modules for address, output range, baud rate, data format, checksum status, slew rate, and startup output value. All programmable parameters are stored in the nonvolatile memory of the module. The current output of the 6B21 is isolated from the power supply and the communications port to 1500 V rms.

The 6B21 module has the same pinout and form factor as the 6B Series input modules and can be used in any position on a 6B Series backplane.

Analog I/0 Features

Sensor-to-Computer Conditioning and Digitizing

Complete 16-Bit Data Acquisition System in Each Module

RS-232C or RS-485 Communication Interface

Field Configurable via Software

Simultaneous Sampling

Configurable Parameters Stored In Each Module

Auto-Calibrating, Linearized Outputs in Engineering Units

Input to Output Isolation :

1500 V rms Continuous - Models 6B11, 6B12, 6B13, 6B21, 6B50

2500 V rms Continuous - Models 6B11HV, 6B12HV, 6B13HV

Easy To Install Specifications Valid Over the -25°C to +85°C Operating Temperature Range

Simultaneous Sampling

Software Configurability

High Performance

High Noise Rejection

Features

24 Channels of Digital I/0

Interfaces with Industry Standard Digital I/0 Panels for Solid State Relays

High Output Current Capability

RS-232C/RS-485 Communications

Command Set Compatible with 6B Series Input/Output Modules

Readback for Output & Status Monitoring

Bit and Byte Addressable

Communication Compatible with Analog I/0 Backplanes

The 6B50 is a digital I/0 board that is compatible with the 6B Series at the communications network level. It accepts a command from the host and converts it to logic levels suitable for interfacing with industry-standard, optically-isolated digital I/0 panels. All I/0 channels can be configured for input or output, using bit or byte addressing. In addition, the status of the port can be read back by the host to confirm the I/O configuration.

An on-board microprocessor in the 6B50 communicates with the host to exchange command and status information. An EEPROM is used to store system parameters (address, baud rate, etc.) as well as I/O configuration information. The microprocessor is interfaced to 8-bit latches and buffers for a maximum of 24 digital I/O channels. Each channel can be set individually as an input or output.

The 6B50 is available with an RS-485 interface (6B50-1), or with an additional RS-232C/RS-485 converter (6B50-2).The 6B50 is an open board that can be panel or rack mounted. It is fully rated over the 0°C to +70°C temperature range. Also available with the 6B50, are 16 - and 24 - channel digital subsystems (DB-16 and DB-24) that interface with the 6B50 through a 50 conductor flat ribbon cable (CAB-03).

Combined with the modules, the 6B Series backplanes provide a complete process monitoring & control system. Each backplane incorporates screw terminals for field wiring inputs and outputs and cold junction compensation for thermocouples. Depending on the option, the communication interface is RS-232C or RS-485, or both.

For application flexibility - one, four and sixteen channel analog backplanes are available. An RS-232C interface allows easy hookup to most PC serial ports, while an RS-485 interface can be used for daisy chaining additional backplanes and can drive a twisted pair cable up to 4,000 ft.

All communications with 6B Series module subsystems consist of commands generated by the host computer and responses transmitted by the 6B Series modules. A "party line" system is employed; all commands to the modules must contain an address, and only the addressed module will reply. All characters transmitted or received from a module are composed of a subset of printable ASCII characters.

Utility Disk: A configuration and test program for the 6B Series allows the modules to be tested on the bench as well as for programming all parameters including: address, range, output format, and checksum enable. Download here.

Drivers: Drivers for popular software packages are also available. These drivers provide transparent access to the 6B Series modules from the serial port, and maintain a user friendly interface. Consult the 6B Series Configuration Guide Section for more information.

The 6B Series delivers sensor-to-host signal-conditioning for remote applications. Software-configurable for a wide variety of sensor types, including: analog input, analog output, and digital I/0, the 6B Series is intended for remote data acquisition, machine monitoring, remote energy management and process monitoring and control applications. Including transformer-based isolation, ranging, linearization, A/D conversion and RS-232C/RS-485 serial communication for up to 256 channels per serial port, the 6B Series modules and boards are a complete, low-cost interface between computers and analog signals. All 6B Series input/output modules are fully encapsulated and identical in pin-out and size, facilitating their ability to be mixed and matched with all other 6B Series modules on the same backplane. The 6B Series is fully rated over the industrial temperature range of -25°C to +85°C.