GASMAX/TX Operation & Maintenance Manual, Revision 1.0
Page 32
TREND AND DUAL DATA DISPLAY SCREENS
Pressing the “NEXT” key allows the user to cycle through the available data and trend screens. In single
channel mode, there are only two screens – Data Display and Trend Display. If both channels are active,
there are two Data Display screens, two Trend Display screens and one Dual Data Display screen that
shows both channels values and alarm status.
Figure 10-2: Dual Data and Trend Display Screens
NORMAL OPERATION
Every six seconds, the GASMAX/TX reads the sensor’s digital output, converts the reading to calibrated
engineering units and displays the value on the LCD display. Based on the gas concentration level and
alarm levels programmed by the user, the microprocessor determines if a compact wireless data packet
should be broadcast to the site manager or wireless controller / receiver. This data packet includes the
gas value, alarm and fault status bits and battery voltage. The GASMAX/TX will initiate a data packet
transmission under the following specific conditions:
•
Every time the
Wakeup Timer
expires, irrespective of the gas level present. This allows controller /
receivers to confirm the presence of the gas monitor or issue a COMM ERROR is no transmission is
received in a fixed interval (default is 18 minutes, but can be adjusted by the user).
•
IF the new reading exceeds the
Alarm 1, Alarm 2 or Alarm 3
programmed value. A sensor FAULT
reading does not initiate a transmission, but will be broadcast on the Wake-Up timer interval.
•
If the reading rises or falls
by more than 2% of full scale
as compared to the last reading.
•
Upon
entry into CAL mode
, a packet containing a gas value of 300 counts (-15.6% of scale) is
transmitted to indicate IN CAL for the current channel.
•
Upon
entry into CAL PURGE mode
, a value of 800 counts (0% of scale) is transmitted for all sensors
except oxygen sensors, where a value of 3475 counts (83.6% of scale) is transmitted.
•
Holding the magnetic wand
over the UP key
until the Data Transmission icon appears.
Channel
Alarm Status
30 Min
Trend
