YOKOGAWA TB400G-A1 Series, User Manual, Page: 116 / 140

<7. MAINTENANCE>
7-13
IM 12E04A02-02E 3rd Edition : May. 31, 2010-00
7.14 Operation During Power Failure and at Power
Recovery
Setting data, the current operation mode and function number are stored in the EEPROM (non-
volatile memory). Accordingly, data are not lost in a power failure.The operation mode and
function number status immediately before the power is turned off are retained unchanged as
long as the re-supply of current is performed. However, operations in the way of execution cannot
be recovered and the initial status is restored in that function number.
If the power fails in the <MEAS.> mode, the internal time is reset upon power recovery.
Thus, automatic cleaning and automatic zero calibration operations start to operate at the
measurement start point in Figure 7.9.
A A
B B B B B B
Cleaning Calibration Cleaning Calibration Cleaning Cleaning
Measuring start (*1)
Calibration period (A) and
cleaning period (B)
F0710.ai
(*1) Measuring start means the time point when
other mode --> <MEAS.> mode, or
power off --> power on (MEAS.> mode).
Figure 7.9 Automatic Cleaning and Automatic Zero Calibration Periods
IF the power fails, SV3 (motor valve) retain the status before the power was turned off (open or
closed). Note that, even if the power fails, they mey not necessarily be closed.
Valves SV1 (pinch valve) and SV2 and SV4 (solenoid valves) are shut.
The contact statuses are as shown in Table 7.2.
Table 7.2 Contact Operation in Power Failure
Contact output Terminals Operation
Maintenance output M1, M2 Closed
FAIL output F1, F2 Open
AUX output C1, C2 Closed
Range output A1, A2
A1, A3
A1, A4
Closed
Open
Open