BECKHOFF FM33xx - Manual (Page 32)

Register description
FM33xx 27
The open circuit and back voltage status information is also requested in a
similar manner by means of the channel selection control bits. When these
have been confirmed in the status byte the status information can be read
from the data for the 4 channels. For each channel that is registering open
circuit, one bit is set in bytes 1 to 4, while bits are set in bytes 5 to 8 for
channels registering back voltage.
Register description
The TC-Plug can be configured via the serial interface using the KS2000
configuration software. The individual thermocouple input channels are
represented in the configuration software as complex terminals.
Each logical thermocouple input channel has its own set of registers.
Various operating modes and functionalities can be set for each channel by
means of the registers.
The "General Description of Registers" explains those register contents
that are the same for all complex terminals.
The terminal-specific registers are explained in the following section.
The registers for a channel can be written to if the code word 0x1235 is
entered in R31 (register 31). The data is only permanently stored when the
code word is cleared and the module is reset.
General description of registers
Complex terminals that possess a processor are able to exchange data bi-
directionally with the higher-level controller. These terminals are referred to
below as intelligent Bus Terminals. These include the analog inputs (0-10
V, -10-10 V, 0-20 mA, 4-20 mA), the analog outputs (0-10 V, -10-10 V, 0-
20 mA, 4-20 mA), the serial interface terminals (RS485, RS232, TTY, data
exchange terminals), counter terminals, encoder interface and SSI
interface terminals, PWM terminals and all the terminals that can be
parameterized.
The main features of the internal data structure are the same for all the
intelligent terminals. This data area is organized as words and includes 64
memory locations. The important data and parameters of the terminal can
be read and set through this structure. It is also possible for functions to be
called by means of corresponding parameters. Each logical channel in an
intelligent terminal has such a structure (so a 4-channel analog terminal
has 4 sets of registers).