GE M60 UR Series

GE Multilin M60 Motor Protection System 5-233
5 SETTINGS 5.7 CONTROL ELEMENTS
5
There are 48 identical digital elements available, numbered 1 to 48. A digital element can monitor any FlexLogic operand
and present a target message and/or enable events recording depending on the output operand state. The digital element
settings include a name which will be referenced in any target message, a blocking input from any selected FlexLogic oper-
and, and a timer for pickup and reset delays for the output operand.
• DIGITAL ELEMENT 1 INPUT: Selects a FlexLogic operand to be monitored by the digital element.
• DIGITAL ELEMENT 1 PICKUP DELAY: Sets the time delay to pickup. If a pickup delay is not required, set to "0".
• DIGITAL ELEMENT 1 RESET DELAY: Sets the time delay to reset. If a reset delay is not required, set to “0”.
• DIGITAL ELEMENT 1 PICKUP LED: This setting enables or disabled the digital element pickup LED. When set to
“Disabled”, the operation of the pickup LED is blocked.
Figure 5–119: DIGITAL ELEMENT SCHEME LOGIC
CIRCUIT MONITORING APPLICATIONS:
Some versions of the digital input modules include an active voltage monitor circuit connected across form-A contacts. The
voltage monitor circuit limits the trickle current through the output circuit (see technical specifications for form-A).
As long as the current through the voltage monitor is above a threshold (see technical specifications for form-A), the “Cont
Op 1 VOn” FlexLogic operand will be set (for contact input 1 – corresponding operands exist for each contact output). If the
output circuit has a high resistance or the DC current is interrupted, the trickle current will drop below the threshold and the
“Cont Op 1 VOff” FlexLogic operand will be set. Consequently, the state of these operands can be used as indicators of the
integrity of the circuits in which form-A contacts are inserted.
EXAMPLE 1: BREAKER TRIP CIRCUIT INTEGRITY MONITORING
In many applications it is desired to monitor the breaker trip circuit integrity so problems can be detected before a trip oper-
ation is required. The circuit is considered to be healthy when the voltage monitor connected across the trip output contact
detects a low level of current, well below the operating current of the breaker trip coil. If the circuit presents a high resis-
tance, the trickle current will fall below the monitor threshold and an alarm would be declared.