6
MJ-5 Control Panel Automatic Mode
Siemens Industry, Inc.
44
6 MJ-5 Control Panel Automatic Mode
This Chapter covers operating principles of the MJ-5
control program and describes the various functions
performed by the microprocessor. It contains the
information you may need when deciding between the
various options described in Chapter 4 (Setting Up the MJ-
5 Control Panel) and Chapter 5 (Reading and Interpreting
MJ-5 Control Panel Data).
6.1 MJ-5 Control Modes
The regulator control function has four operating modes:
local manual control, local automatic control, remote
control, and Off. Manual control can only be performed
locally. Select the operating mode with the Remote-Auto/
Off/Manual switch as shown in Figure 6.1.
Figure 6.1
Auto/Manual Switch (Shown in Off position)
Manual mode
Place the Auto/Off/Manual Switch in the down position to
activate the Manual mode. In Manual mode, you can use
the Tap Raise/Lower switch (on the MJ-5 front panel) to
control the tap position directly. Status information is
available via the remote communications link, but the
remote operator cannot change settings or otherwise
operate the MJ-5 Control Panel.
Off (By-Pass Position)
No operation of the tap changer can occur: remotely,
locally, or automatically.
Table 6.1
Summary of Control Mode Operation MJ-5
Auto-Remote mode
With the Auto/Manual switch in the up position, the
Remote/Local key may be pressed so that the Remote
Disabled LED is off, putting the control Panel into the
Auto-Remote mode.
In this mode, the MJ-5 executes its automatic tap control
algorithms, unless overridden remotely. Status information
is available via the remote communications link. A remote
operator can request a tap raise or lower via the
communications link, change settings and remotely operate
the control program. For direct control via terminal strip
connections see Figure 2.3.
When the remote operator initiates the tap raise/lower, the
MJ-5 enables its “Pseudo-Manual” operating mode.
The Pseudo-Manual alert condition is activated, and local
automatic operations are disabled until the remote-
commanded tap raise/lower is completed.
The MJ-5 Control Panel remains in the Pseudo-Manual
mode for a predefined time period after receipt of the last
remote tap raise/lower command. When the time period has
elapsed and the MJ-5 Control Panel has Remote Auto
Inhibit disabled, the panel resumes its normal automatic
control operations. If Remote Auto Inhibit is enabled, it
maintains its tap position until it receives another
raise/lower command or until Remote Auto Inhibit is
disabled.
Auto-Local mode
With the Auto/Manual switch in the up position, if the
Remote/Local key is pressed so that the Remote Disabled
LED is on, the control Panel will be in the Auto-Local
mode. In this mode, the MJ-5 executes its normal tap
control algorithm. Status information is available via the
remote communications link, but the remote operator
cannot change settings or otherwise operate the MJ-5
Control Panel
Table 6.1 summarizes the four operating modes.
