Vaisala MMT330 - Manual (Page 64)

User's Guide _______________________________________________________________________
64 ___________________________________________________________________ M210764EN-F
already in memory. However, the data of any removed quantity cannot be
accessed unless the quantity is re-activated first.
The data logger module has a real time clock with a battery back-up. The
clock has been set to the Coordinated Universal Time (UTC) at the
factory, and its time cannot be set by the user. The data that is stored in
the logger's memory is timestamped using the logger's clock.
When date and time are set on the transmitter, they are stored to the
transmitter's memory as an offset from the time on the logger's clock.
When browsing the stored data, the time offset is applied to the
timestamps shown in the graphical history, and data outputted from the
serial port. The timestamps in the data logger's memory remain as they
were originally stored.
You can compensate for the clock drift (less than ±2 min/year) by setting
the time on the transmitter. This updates the time offset used on the
display and the serial port. You can set the time by using the
keypad/display or the serial commands.
1 = Flat cable pins
2 = Battery
0706-068
Figure 38 Data Logger Module
After a reset or a power up, it will usually take at least 10 seconds before
the data logger module is initialized. The instrument will not start up
before the data logger module is ready.
The indicator LED on the module will blink green during normal
operation. If the LED is lit in red color, there is a problem with the
module. The transmitter will also indicate the problem by activating the
"Internal error on add-on module" error. If the module is not operating
correctly, the transmitter must be sent to Vaisala for maintenance.
The data logger module must be installed at the factory (when ordering
the transmitter), or by a Vaisala Service Center. Once installed, the
module is automatically used by the transmitter. When the module
requires a new battery, the transmitter must be sent to Vaisala for
maintenance.