8 MJ-4A & MJ-4B Control Panel Basic Troubleshooting
Siemens Energy, Inc. 57
Note: If password protection is in effect, you must
enter the password to enable calibration. The
default password for the <DIAGNOSTICS>
Menu is “3333”.
Repeat the above procedure for C/C2 Medium and C/C2
High. After calibration, replace J1 and Terminal Strip
jumper at P3B-11 & 12.
Note 1: Prior to calibration, disconnect panel from regulator, and remove on-board jumper J1 (see Figure J.1) and Terminal Strip jumper at
P3B-11 & 12. After calibration, replace J1 and Terminal Strip Jumper at P3B-11 & 12.
8.5 MJ-4A & MJ-4B Self Testing
After reset, the MJ-4
runs through an internal diagnostics
routine. The start-up diagnostics routine includes a front
panel indicator test—the LED indicators simultaneously
flash three times so that an operator can verify them. Dur-
ing the LED test, the MJ-4
displays “Testing...” on the
front panel screen.
The start-up diagnostics routine consists of several checks
and internal tests, including a ROM (program memory)
checksum calculation. The MJ-4
displays the results of
the checksum test (PASS or FAIL) in the “Checksum=”
item under the <DIAGNOSTICS> Menu.
A checksum failure indicates a problem with the unit. A
checksum or other self-test failure will activate the “Self
Test Fault” message. If this message occurs, contact
your Siemens Power Transmission & Distribution repre-
sentative for instructions.
8.6 Communications Module
Troubleshooting
In the <DIAGNOSTICS> Menu, the MJ-4
Control Panel
provides data items for testing the Communications Mod-
ule and verifying its operation. Please refer to the MJ-4
Communications Module Installation Manual for verifying
the Communications Module operations using the
<DIAGNOSTICS> Menu data items.
8.7 Tap Tracking
When viewing this alert, press the left arrow key repeat-
edly. On the right side of the screen two character error
codes will appear. There could be between one and four
of these codes. Note that the codes could have been gen-
erated all at once or at any time since the alert was last
cleared. The codes are:
UX: occurs if algorithm can't tell direction tap change occurred or if
operation count increases without calling for a raise or lower
RS: occurs when neutral signal is on and tap pos is not neutral; panel
resets tap position to neutral if Tap Resync is turned on
TT: occurs if Tap Resync is on and bad neutral signal and tap position
combo persists for more than 10 seconds
OD: occurs if "tap_chg_ctr" goes down to zero before a tap change
occurs. tap_chg_ctr = R/LOnTime + TapChgT/O
Tap Changer control may be customized using the follow-
ing settings from the <DIAGNOSTICS> menu.
R/LOnTime:
maximum time to keep the tap changer motor running
before pausing for R/LOffTime.
R/LOffTime: pause between tap changes for this amount of time.
Fixed R/L On time:When in Auto mode, if this setting is “Y”, motor
stays on for exactly R/L On time seconds.
TapChgT/O: if the control runs the tap changer motor for R/LOnTime
and no operations count occurs, then after this many more seconds a Tap
Track Err OD alert is generated.
TapI n: defines the operations count signal input line.TapInType: defines
the operations counter type.
TapInPulse: defines the minimum amount of time that an operations
count signal must be present in order for the operations counter to incre-
ment (applies to Pulse type operations counters only).
NeutralIn: defines the neutral signal input line.
NeutralCount: number of Neutral positions (for LTC’s only).
Table 8.2 Voltage and Current Calibration
Signal to
Calibrate
Test Signal
Application
Point
Test Signal
Measurement
Point
Nominal
Calibration Signal
Magnitude
Tolerance MJ-4
Data Item
<DIAGNOSTICS>
Menu
Conditions
U2 U2 to E
(P2A-8 & 6)
Voltage Calibration
Ter mi na ls
120 VAC (RMS)
±0.5 VAC U2 Cal U2/P2 key
= U2
P2 P2 to E
(P2A-4 & 6)
Voltage Calibration
Ter mi na ls
120 VAC (RMS) ±0.5 VAC P2 Cal U2/P2 key
= P2
C/C2
Low
C2 to E1
(P2A-5 & 7)
C/C2
(P3B-11 & 12)
5 mA (RMS)
±0.2 mA C/C2low Note 1
C/C2
Medium
C2 to E1
(P2A-5 & 7)
C/C2
(P3B-11 & 12)
80 mA (RMS)
±0.5 mA C/C2med Note 1
C/C2
High
C2 to E1
(P2A-5 & 7)
C/C2
(P3B-11 & 12)
140 mA (RMS) ±0.7 mA C/C2high Note 1
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