Valeport Ltd © 2019
Installation and Operation
Page 9
2.1.2. Electrical Connections
Pin out details are provided in Appendix 1.
2.1.3. Communications Leads
For test, setup and evaluation purposes, the unit should be connected to a PC using the interface lead (Y
Lead) supplied.
The Model 803 can output digital data in either RS232 or RS485 formats. Units are supplied as standard with
RS232 interface leads, but if the user intends to operate the instrument in RS485 mode, then an RS485
interface lead should be purchased in place of or as well as an RS232 lead.
The Y lead consists of a short Subconn type pigtail, which connects to the instrument. A small polycarbonate
box sits in the centre of the lead, with two further cables exiting. The first is terminated with a 9 pin D type
connector, which should be connected to the serial port of a PC. The second lead terminates in two 4mm
banana pins for application of DC power – connect the red pin to +ve voltage, and the black pin to ground or
–ve voltage.
The user will also notice that the polycarbonate box has 4 jack sockets in the side. These are for the analogue
output option of the instrument, if fitted.
In RS485 systems, the polycarbonate enclosure contains an RS485/RS232 adaptor. The user will be able to
communicate with the PC perfectly normally when using this interface unit, but the differential signal allows
communications over long cable lengths.
2.2. Operation
The unit is made operational by applying power. A software program, ROVLog, is provided to allow easy
setup and data display, but some users may wish to simply take the ASCII text output into other systems.
Such users will need to be aware of how to setup and operate the unit using the following commands.
Note that instructions for operation of ROVLog are in a separate document.
2.2.1. Data Output Communications
The data output communications protocol is:
Selectable baud, 8 data bits, No Parity, 1 stop bit
In order to change the set up of the unit and enter the desired baud rate it is necessary to interrupt the unit
and send the appropriate “#” code. For sensible data to be displayed the baud rate at which the unit is
running needs to be known. The original factory baud rate is 19200. The baud rate may be found by
disconnecting, scanning through the four possible baud rates (2400, 4800, 9600 and 19200) in terminal and
re-connecting each time. It should be noted that high sampling rates and low baud rates will not work. This
is due to clashes between the sampling and data output times.
1.
Connect directly to the unit using a terminal program [such as HyperTerminal].
2.
Switch on power and repeatedly send a “#” character to interrupt the unit. The unit will respond with a
“
«
” when interrupted. This interrupting “#” command can be sent at any time when the unit is
powered up in order to interrupt the unit.
3.
The commands which are available are detailed below.
Please note that <cr> denotes the Enter (or Return) key should be pressed.
