Application note PD 640

Analogue input/output: 4 x (0-20mA / 4-20mA)

Feature overview:

The PD 640 contains 4 analogue channels, of which 2 channels can be configured for analogue input or analogue output, and 2 channels are permanent analogue inputs.
When a channel is used as an analogue output, the input channel reads back the actual current of the output.

All PROCES-DATA modules are based on the Channel concept. A channel is a functional object, consisting of functions and all function related data.

A PD 640 Module consists of 3 channel types:

Service channel:
Analogue Input/Output channel:
Analogue Input channel:

General module behaviour and interface.
Functions and data for analogue input / output.
Functions and data for analogue input.

An Analogue Input/Output channel in a PD 640 module is identical to an Analogue Input channel except for the addition of two output registers:

Percentage output and Scaled output

Also, the channel configuration enables the selection of input or output:

Signal type

Analogue Input channel description:

Input channels provided by PROCES-DATA contain much more than just the basic input function. The input channel functions and associated parameters are formed into a channel description. The module’s integrated controller handles all channel functions.
Functions need only to be configured for operation. No additional programming is required.

Analogue Input Channel monitors:

Signal out of range
Wire broken (4-20mA mode only)

Analogue Input Channel functions:

Input signal scaling to SI unit
Analogue Input Filter

Analogue Input/Output Channel functions:

Output percentage
Output scaled

Related Topics

Transmitter installation
PD 641 Application Notes (Pt100 / Pt 1000)
PD 642 Application Notes (mV / thermocouple)
Analogue modules