Changing Setpoints - GE 745 Instruction Manual

CHANGING SETPOINTS

1.3 Changing Setpoints
1.3.1 Introduction
1.3.2 Using the HELP Key
1.3.3 Numerical Setpoints
1–6
There are several different classes of setpoints, distinguished by the way their values are
displayed and edited. This section describes how to edit the values used by all setpoint
classes.
Hardware and passcode security features are designed to provide protection against
unauthorized setpoint changes. Since we will be programming new setpoints using the
front panel keys, a hardware jumper must be installed across the setpoint access terminals
(D9 and D10) on the back of the relay case. A keyswitch may also be used across these
terminals to enable setpoint access. Attempts to enter a new setpoint via the front panel
without this connection will be unsuccessful.
Each numerical setpoint has its own minimum, maximum, and increment value associated
with it. These parameters define what values are acceptable for a setpoint.
1. Select the
S2 SYSTEM SETUP
setpoint.
VOLTAGE
NOMINAL VT SECONDARY
VOLTAGE: 120.0 V
2. Press HELP. The following context sensitive flash message will appear for several
seconds. For the case of a numerical setpoint message, the HELP key displays the
minimum, maximum, and step value.
Range: 60.0
to 120.0 by 0.1
The following two methods of editing and storing a numerical setpoint value are available.
1. 0 to 9 and the decimal key: The relay numeric keypad works the same as that of any
electronic calculator. A number is entered one digit at a time. The left-most digit is
entered first and the right-most digit is entered last. Pressing the ESCAPE key, before
the ENTER key, returns the original value to the display.
2. VALUE keys: The VALUE UP key increments the displayed value, by the step value, up to
the maximum value allowed. While at the maximum, pressing the VALUE UP key again
will allow setpoint selection to continue from the minimum value. The VALUE DOWN
key decrements the displayed value, by the step value, down to the minimum value.
Again, continuing to press the VALUE DOWN key while at the minimum value will
continue setpoint selection from the maximum value.
VOLTAGE INPUT NOMINAL VT SECONDARY
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745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 1: GETTING STARTED