ELECTRONIC PERSONAL DOSEMETER HANDBOOK
EPD/HB/40521/000
APPENDIX C
ISSUE 5
Thermo
Page
99
In built
Integrity
Checks
Detector Test
Regular ‘flash LED’ detector test, also available on
demand over the communications link, at time of
issue. The test takes approximately 1 to 2 ms, during
which time normal dose measurement is inhibited.
Non
volatile
store.
Dose data copied to non-volatile store every 15
minutes ( and more regularly to dose profile ).
Processing
/
Memory
checks.
Critical data areas, dose stores, calibration factors,
communications data, are all protected by powerful
16 bit polynomial crc ( Cyclic Redundancy Check ).
Calibration.
EPDs normally supplied with Calibration factors in the
‘locked’ state and only changeable by Thermo. On
request Thermo will supply units with calibration
factors unlocked.
Dose
Data
verification
User ‘dose’ readings also include detector counts and
associated ‘quality’ data such as impact counts, reset
counts, fault data. Dose and count data may be
‘sensibility’ tested .
ADS Facilities
ADS Issue
EPD may be ‘permanently’ issued by ADS but also
used on an access control system ( by the same
wearer ).
ADS Store
Dose and supporting data is accumulated in an
additional password protected ADS store.
System
Integration
Facilities
Messaging
Interface
A powerful and efficient messaging interface allows
fast and secure data transfer and speedy issue and
return times. Data is protected by 16 bit crc. Issue
and Return times take circa 1 second. Returns take
longer if extensive dose profile data is being
extracted.
EPD Identity
Every EPD has a unique serial number provided on
the case label ( numeric and bar-coded ) and
duplicated in internal memory. The latter is
accessible over the communications link.
Mark
Number Every EPD is manufactured to a defined Mark
Number which is detailed on the case label and
duplicated in internal memory. The latter is accessible
over the communications link.
Wearer
ID
(User ID)
12 character numeric wearer ID, displayable on EPD
LCD ( both control and ADS wearer IDs ). By
convention the wearer ID for a non-issued EPD is set
to FFFFFFFFFFFF.
Wearer Name
22 character wearer name ( may be used but is not
essential ). For version 11 firmware and later the first
12 characters of the wearer name may be displayed
