PT495 Series Detector
(Ultra1000)
Rev 5.11
33
Modbus Registers
Description
40001
Current Gas concentration detected by the sensor
40002
Current Sensor status ( bit map). See explanation later in this
section
40003
Current Alarm 1 set point or level
40004
Alarm 1 relay type. Value is 0 for non-latching, 1 or latching
40005
Current Alarm 2 set point or level
40006
Alarm 2 relay type. Value is 0 for non-latching, 1 or latching
Relays
40007
Reset currently active alarm relay via MODBUS.
Writing 1
to this register will reset alarm relays
The status register is used for sensor type and alarm status bits. Each register is
a 16 bit (2 byte) register. The value of the high order (most significant) byte of
status register determines the type of sensor while each bit in the lower byte of
the register determines a particular condition like active alarms or sensor
malfunction. The table below shows the high byte value of status register
returned by the sensor and the corresponding sensor type.
Sensor Type
Value of High Byte in Status
Register
H2S
01
LEL
02
SO2
03
CO
04
Oxygen
05
Hydrogen
06
Call Factory for Additional Type Code
Note:
for all the sensors with display resolution of 1/10, the alarm levels and the gas levels
are updated as 10 in MODBUS Registers. For example the gas reading of 10.5 (ppm or %Vol)
will be updated as 105.