GD10P User Manual Page 39 of 44 850-811250-Rev.06b
11 APPENDIX 1 - GENERIC HART® COMMANDS
Current Gas reading
Read Primary Variable (command #1), returns the current gas reading.
Detector Variables
“Read all dynamic Variables and Current” (Command #3), returns the following:
• “Secondary Variable”: Current internal temperature of the detector
• “Tertiary Variable”: Current strength of the optical transmission path
• “Fourth Variable”: Maximum temperature the detector has been exposed to
Detector Information
Through standard HART® Universal commands (detailed user interface vary from one HART®
terminal to another), specific information may be written to the detector and read back from the
detector. Information supported: Tag, Descriptor, Message, Date and Detector Serial Number.
Configure Detector Response Time
“Write Damping Value” function (command #34) is used to configure the detector response time.
“Damping Value” = 1 turns the detector to Fast mode (1 second response time) and “Damping
Value” = 5 turns the detector to Normal mode (5 second response time).
Zeroing
“Set Primary Variable Zero” function (command #43) is used when trimming of the zero level of
the gas detector is required. When the Set Primary Variable Zero is activated, the analogue
output is dropped down to 1mA to indicate the on-going zeroing process, which takes about 3
minutes to complete. The analogue output returns to the actual zero (4mA) when zeroing process
is completed. If the Zero level is not improved after the zeroing, the reason is that the zero drift
is over the allowed limit for field trimming.
To Next Page
Loading...