Xylem iRIS 150 GPRS DATALOGGERS - Manual (Page 26)

iRIS 150 V1.11 User Guide - 20
20 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
5.3.8 Miscellaneous Menu (Level 2)
This menu covers the miscellaneous configuration items.
* Miscellaneous
0 Exit
1 Addr [1]
2 SDI-12 Timing [2573]
3 SDI-12 Terminal
4 Initialise
>
Option 1
When this option is selected you will be prompted to enter the System DO  address for the device.
> Address=
Enter a value between 0 and 32767 (the factory default is 1). This address is used to identify the unit in all
System DO
 communications.
NOTE: An address of 0 is normally reserved for the base station (e.g. HydroTel™ 2000). The iRIS will
always respond to an address of –3, which is a special universal address.
Option 2
The SDI-12 communications protocol defines several timing criteria that all equipment should comply with.
In particular there is a minimum break time before a command in order to allow a sensor to wake up and
respond. Some sensors are slower to wake then others and this can be catered for by issuing retries or
extending the break time. The SDI-12 specification defines a retry sequence to handle slow or non-
responsive sensors. The IRIS SDI-12 function operates in such a way that absolute inter-retry timers may not
be absolute. Therefore a timing adjustment register is provided that allows the pre-command timing to be
extended.
For space reasons this register in fact contains two timing values which are combined into a single number.
Although unfriendly to the average user, it can be easily adjusted. The register value is made up of a break
time and space time, both in milliseconds.
SDI12Timing = (BreakTime *256) + Space Time
The default values are Break Time = 10 and Space Time = 13
So (10 *256) + 13 = 2573 which is the default value.
Normally this register should never need changing, but if a sensor is non-responsive or intermittently
unresponsive, extend the timing out. Typically a value of 19981 will ensure that any sensor type will respond.
Option 3
The SDI-12 terminal mode allows direct access to instruments connected to the SDI-12 interface. This is
useful when a manual check or changes need to be made, such as address changes, scale factors etc.
Knowledge of SDI-12 commands is required to make best use of this feature.
> SDI-12 Terminal mode active. Press <ESC Enter> to exit
NOTE: This menu option will only appear if one or more sensors have a source set to SDI-12.
When using transparent terminal mode you must press the <Enter> key after each command or message
you wish to send. Press ESC then Enter to exit the modem terminal session and return to the communication
menu.