Hydrological Services Pty Ltd
Data Logger Model ML1-420
©
Copyright
ML1-420 100-8
Issue 1.00 6 Apr, 2011
2.
When the ML1-420 is directly connected to a PC, sufficient power is extracted from the
handshake signals to power the ML1-420 – which prevents power drain from the internal
battery while communications is in progress.
3.
A solder link LK1 on the ML1-420 PCB allows the digital input from the TBRG to be
connected through pin 9 of the DB9F connector. See section 3.1.1 for more details.
The DB9 female connector on the logger is the communications port and is setup as a DCE.
This allows direct connection to a PC comm port using a DB9 male to DB9 female 1-to-1
cable. (The minimum connection is pins 2, 3, 4 and 5.)
Minimum Connection of PC on DB9F
Communications can also be active while the contact closure input on pin 9 is used when
jumper LK1 is soldered, and a special cable is prepared.
Connection of PC together with Contact Closure Input through the DB9F
PC
Comm
Port
1
8
MiniLog
ML1-420
2
3
4
5
6
7
9
DB9
Female
1
8
2
3
4
5
6
7
9
DB9
Male
PC
Comm
Port
1
8
MiniLog
ML1-420
2
3
4
5
6
7
9
DB9
Female
1
8
2
3
4
5
6
7
9
External Voltage
Free Contact
(TBRG)
DB9
Male
Contact
monitor
LK1
Tx
Rx
DTR (pulled high)
Gnd
