Delta OHM D35ED-ALM, Руководство пользователя

Страница: 10 / 88

- 10 -
The maximum number of devices that can be added to a base unit depends on the data
transmission interval, as indicated in the following table.
TAB. 3.1: Number of devices manageable by the base unit
Data
transmission
interval
Number of devices
manageable by
the base unit
Data
transmission
interval
Number of devices
manageable by
the base unit
1 s 12 10 s 120
2 s 24 15 s 180
5 s 60 > 30 s 254
The table refers to the condition of direct transmission between base unit and data loggers (1
"Hop"). In the presence of repeaters, the data transmission requires more time, and the num-
ber of devices manageable by the base unit could be lower than the one indicated.
9. C
HECKING THE QUALITY OF RF COMMUNICATION
The correct RF communication between base unit and the other devices connected to the net-
work can be checked in the following ways:
• In the main window of the HD35AP-S software, by checking that the RF signal level re-
mains high, that the strength of the received signal RSSI (Received Signal Strength Indi-
cation) exceeds -85 dBm and that the percentage of transmission errors PER (Packet Er-
ror Rate) is close to zero.
Fig. 3.7: verification of RF communication with HD35AP-S software
• In data loggers with display, by checking that the strength of the received signal RSSI
exceeds -85 dBm and that the percentage of transmission errors PER is close to zero.
Use the button to display RF RSSI and PER quantities.
• In the devices without display, by briefly pressing the connection button (PING function)
and by making sure that the green RF LED blinks for a few seconds;
10. I
NSTALLING THE DEVICES
After a bench test of the system, proceed with the individual installation of the devices in the
final work location.
If data loggers using external probes with cable are installed, place the probes in the environ-
ment to be monitored and connect them to the data loggers (for the connectors layout, see
paragraphs Data logger models in indoor-use housing on page 26 and Data logger models in
waterproof housing on page 51).
11. C
HECKING WHETHER THE DEVICES ARE REACHABLE
After installing the devices, you need to verify again the correct RF communication between
the base unit and the other devices of the network, in order to make sure you didn’t place the
devices too far from the base unit or in places that make RF transmission difficult (shielded
environments or with several obstacles). To check RF communication, proceed as indicated at
step 9.