I had planned to install an RS232-to-USB cable on a CR200X and leave the cable permanently connected to the logger.
Because the logger has to run on batteries, I checked the standby current and saw that it raises from 0.25mA without cable to 1.03mA with RS232-to-USB cable (cable not conncted to the pc on the USB side).
I'm astonished about this, since when I used the same type of cable with CR1000 or CR800 loggers, the standby current didn't rise.
Is there a possibility to eliminate the current rise on the CR200X?
* Last updated by: Monte on 8/8/2013 @ 2:33 PM *
The CR200 shuts off its RS232 port driver chip like the other loggers but it does not support active handshaking lines. Instead these (pins 6 and 8) are tied permanently to an internal 5V supply via 330 ohms. This is so it will work with computers/interfaces that require those lines to be high. That will be the cause of your current drain, as the nominal input impedance of RS232 inputs is about 3K.
The logger itself will work without these lines connected. You could try making a simple 3-wire cable (TX, RX and G) between the logger and the USB interface which will cut the power drain. You may need to change the settings in the controlling software if it requires high handshaking lines to work.
Thanks for this information. I decided to cut-off the handshake lines inside the logger. I took apart the CR200X, located the pin on the socket header which connects the terminal board with the processor board and cut the pin off. (It is one common pin for both handshake lines. On the processor board, innner row, 5th pin from lower end.)
It's working fine!