Owner's Manual

GDX-350 Sensor Transmitter
8 P/N: 5600-9001 Rev 2
1.3.2 RF Comm Cycle and Conserving Battery Life
Most of the GDX-350’s battery power is consumed as the radio communicates to the wireless network.
Each Comm cycle consists of the following operations: Awake the radio in receive mode; listen for the
Server’s beacon; synchronize to the Server’s hopping frequency to become “In Range
”; transmit data
packet out the antenna and return to sleep mode. This sequence takes from 0.25 to 1 second to
complete. If the radio fails to synchronize hopping upon the initial attempt, it waits 6 seconds and tries
again, then waits 6 seconds and tries once more. If the third attempt fails, the “Out of Range
” icon
appears and the GDX-350 returns to its Comm cycle. Out of Range will also be logged into the Event
Log. Transmit power levels are adjustable (900MHx models only) and the lower the power setting the
longer the battery will last.
Every 6-seconds, the monitor performs a “sniff test” to detect level of target gas present at the sensor. At
each “sniff test”, the Zzz’s “Sleep Mode” icon is briefly replaced by an RS icon. At this time the readout
updates to indicate gas value measured at the “sniff test.” The
radio
The following list identifies each of the conditions that cause the radio to transmit:
stays OFF if the gas value does not
trip A1 or A2 alarms. Except when the Wakeup Time menu expires (maximum of 5-minutes) the radio
turns on, receives the Server’s beacon, and transmits its data. These routine transmissions allow the
controllers to confirm a good wireless comm link even when no alarms exist. If A1 or A2 alarms do exist
during the “sniff test”, the radio wakes, receives the Server’s beacon, and transmits its data immediately.
• Every 5-minutes (or faster depending upon Wakeup Time menu) when there is no A1 or A2
alarm.
IMPORTANT: The receiving controller reports “Comm Error” if the monitor does not
reply for periods of greater than 18-minutes. A3 and FAIL alarms do not increase radio
transmission rates.
• Every 6-seconds if there is an A1 or A2 level alarm.
• Upon entry into CAL MODE a 75 counts value (-15.6% FS) is transmitted. Receivers indicate “IN
CAL” when 75 counts is the input for a channel (200 to 1000 counts represents 0 to 100% of full
scale).
• Upon ENTRY into CAL PURGE a 200 counts value (0% FS) is transmitted.
NOTE: To prevent A1 & A2
low trip alarms, oxygen
ranges transmit 20.9% readings upon entry
into CAL PURGE.
• Holding the magnet to the UP key for >8 seconds forces a transmission of the current reading
value.
1.3.3 RF BATTERY I/O PCB WITH POWER SWITCH
The RF electronics consists of the lower Battery I/O PCB (Figure 1-3) connected by a cable to the upper
Display assembly with RF Module PCB (Figure 1-4). The 3.6 volt lithium ‘D’ cell battery will continuously
power the unit for up to one year and may be replaced by following the procedure in Figure 1-3.
Power switch (SW1), on the Battery PCB, applies battery power to the RF monitor. SW1 should be OFF if
the monitor is to be out of service for long periods.
IMPORTANT: Do not turn SW1 ON until the controller designated as
Server is fully
operational and ready to communicate to the RF-equipped GDX-
30s. Battery life is
reduced if the RF-equipped GDX-30 is on for long periods while unable to communicate to
the Server controller.
IMPORTANT: DO NOT ATTEMPT TO CHARGE THIS BATTERY OR REPLACE WITH
ANY OTHER THAN THE APPROPRIATE PART FROM BACHARACH.