a division of Zoltech Corporation

VolksMeter II

Seismometer/Tiltmeter

 

Frequently Asked Questions

 
I want to build my own RS232 extension cables.  What are the pinouts of the RS232 connectors on the VolksMeter I/O panel?
The COMM port is a DE-9S connector for communication with the support computer
  Pin
1
2
3
4
5
6
7
8
9
Function
N/C [No Connection]
Receive Data (to support computer)
Transmit Data (from support computer)
Data Terminal Ready (from support computer)
Ground
N/C
N/C
N/C
N/C
  The GPS port is a DE-9P connector for communication with the GPS Receiver/Antenna
  Pin
1
2
3
4
5
6
7
8
9
Function
1 Pulse Per Second (from GPS)
Transmit Data (from GPS)
Receive Data (to GPS)
+5V (from VolksMeter)
Ground
N/C
Ground
N/C
N/C

How long can the extension cables be?

  That is hard to give a specific answer to.  It depends on several factors including:
     1) The data (or baud) rate.  The slower the data rate, the longer the cable can be.
     2) The quality of the cable.  Low capacitance, shielded cables can be longer than high capacitance or unshielded cables.
     3) The electrical noise environment.  A low-noise environment will allow longer cables.

As an example of what does work, at the RLL Instruments facility, we have connected the support computer to the VolksMeter with a 9-conductor, unshielded ribbon cable that is 25 feet long using the default data rate of 38, 400.  The GPS Receiver/Antenna is mounted on the roof of our building, at the end of 100 feet of 3-pair, unshielded twisted-pair, Category 3 (Voice quality) cable.

Because of differences in the environment where you will be using your VolksMeter, you will have to experiment.  Your mileage may vary.


 

   

16009 Arminta Street, Van Nuys, CA 91406 USA - 818-780-1800 - FAX 818-780-1978 - http://rllinstruments.com

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