Operation Principle - ABB RELION REX640 Technical Manual

1MRS759142 C
3.15.3
REX640
Technical Manual
Both function blocks have limit supervision alarm outputs and an output for sensor
fault.

Operation principle

The operation of Slot#-mA#/RTD# can be described with a module diagram that
illustrates a single input-output combination of the actual function block. All the
modules in the diagram are explained in the next sections.
Slot# – Input #
GUID-24BE3C0D-4230-4FE2-ADF6-FC216363E9E0 V1 EN
Figure 52: Functional module diagram for input mode
AO_VAL
GUID-49FE9E17-1171-42FF-BCEA-C3ADEDF2B018 V1 EN
Figure 53: Functional module diagram for output mode
mA modules
Channels 1 and 2 are used for input current measurement or output current control in
the range of -20...20 mA (DC current). The channels are configured for particular
input or output signal types by using channel-specific settings. When Input 1 is
activated with setting "-20...20mA", the Output 1 mode is blocked. If Output 2 mode
is activated with setting "-20...20mA", the Input 2 mode is blocked. When a channel
is configured as an output, the alarm outputs are deactivated.
RTD modules
Channels 3...12 are used for resistance measurements and they are only input
channels. The inputs are configured for a particular input signal type by using the
channel-specific Input mode setting. The default mode for each channel (1...12) is
"Not in use" which means that the channel is not sampled and the output value quality
is set accordingly.
mA/RTD
module
AI_RANGE#
HIGH_ALARM
Limit
supervision
HIGH_WARN
LOW_WARN
LOW_ALARM
mA
Slot# – Output #
module
Section 3
Basic functions
AI_VAL
AI_DB#
159