Installation; Optional Check Source Use (450 Ucs); Theory Of Operation - Fluke 481-DESI Operator's Manual

If chamber bias is LO, the instrument can't measure high
radiation rates accurately. Service to the instrument is required.
If the unit passes the self-test, it will go into the normal operating mode. If the unit fails
the self-test it will remain locked with the firmware revision displayed. Contact Fluke for
corrective action. See the How to Contact Fluke section in this manual.

Installation

The Model 481 periodically tests for mark signal at its RS-232 port. When an RS-232
signal is detected, the Model 481 sends test signals using its sending device and, if
RS-232 is present and operational, the survey meter will enter into the communications
mode. The 481 display will clear and the letters "CO" will be displayed as an indication
that the unit is in the communications mode.
The 481 is compatible with a CRT or printing terminal having a standard RS 232
connector and a 1200-baud rate. A computer with a modem or terminal emulator may be
used in place of the terminal. The terminal or computer should be set up for 1200 baud,
7 data bits, no parity bit, and 1 stop bit.
1. Connect the 9 pin female connector to an active communication serial port.
2. When "CO" appears on the 481 display, press the computer or terminal space bar
twice.
If the Model 481 displays the "CO" message but there is no response at the terminal after
pressing the space bar twice, perform the following tests:
Be sure that the 481 and terminal are properly connected via the RS-232 cable.
If there is still a problem, contact Fluke for further instructions. See the How to Contact
Fluke section in this manual.

Optional Check Source Use (450 UCS)

The check source contains radioactive materials, used for the
verification of survey meter operation. Use care in the handling
and storage.
To check the Model 481, perform the following:
1. Turn instrument on and allow one minute to warm up.
2. Open the beta shield.
3. Place the check source flat against the end window.
4. Check for a nominal reading of 0.4 mR/h (4 Sv/h).

Theory of Operation

This unit contains lithium cells with a potential voltage of 63 V
on the battery assembly. Use care in handling this assembly
during removal and installation. Damage to the instrument or
bodily harm may result.
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Theory of Operation
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