Gentec-EO T-Rad (DB-15) - Manual (Page 18)

T-RAD-DB15--USB Instruction Manual Version 2.1 December. 2012 18
Scale Index Range
2fW 00 2 femptowatt
20fW 01 20 femptowatts
200fW 02 200 femptowatts
2pW 03 2 picotowatts
20pW 04 20picowatts
200pW 05 200 picowatts
2nW 06 2 nanowatt
20nW 07 20 nanowatts
200nW 08 200 nanowatts
2uW 09 2 microwatts
20uW 10 20 microwatts
200uW 11 200microwatts
2mW 12 2 milliwatts
20mW 13 20milliwatts
200mW 14 200 milliwatts
2W 15 2 Watts
1.4 Data Format
Measurement Data is sent from the T-RAD as an Hexadecimal string.
PPPP,DDDCRLF
PPPP is the pulse period counts. 1 million counts represent 1 second.
DDD is the pulse data in ADC counts with 3276 being full scale.
Example:
Data = 99F9,1B4CRLF and T-Rad is in the 2mW range (index 12)
The pulse is 0x1B4, or 436 counts.
The reading will be 436 / 3276 x 2mW = 0.266mW
The period is 0x99F9, or 39417 counts.
1E6 counts / second / 39417 counts = 25.37Hz.
1.5 Instrument Connections
The T-RAD is connected to the host PC with a supplied USB cable. The instrument communicates
with the host PC via this cable, and the host PC supplies the power required by the instrument.
There are two BNC ’s and one DB15 connector on the instrument. The probe in use is plugged into
the DB15 connector and must be plugged in before connecting the USB cable. One BNC is labeled
Detector Output; the other is labeled External Trigger In.
The Detector Output BNC supplies a buffered signal that is the same value sampled by the
instrument
’s ADC. The output impedance of this connector is 100Ω.