24 device initialisation and polling – Tyco MX4428 User Manual

Page 129

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Document: LT0273

MX4428 MXP Engineering / Technical Manual

Device

Processing

Issue 1.5

24 March 2006

Page 9-19

9.24

DEVICE INITIALISATION AND POLLING

The following actions are taken for each device when it powers up or when the MXP powers
up. One action is performed on (or instead of) each 5 second poll.
• If fault bit was received, use HEALTH command to verify that fault was caused by

powerup.

• Use READEE command to check type.

• Send SETALL command to select which values are returned, to set the interrupt

thresholds (if any), set the Digital Outputs required for correct operation and set the
status register for LED blink if required.

• Use READEE command to get factory calibration value for Photo and CO devices.

• Use READEE command to get factory “clean air” value for Photo and CO devices.
• Use READEE command to get the stored LED blink bit. This may require the SETALL

command to be sent again.


Once this is complete FASTAV commands will be used to read the analog inputs (FASTDI
command for RIM) on each poll, except for the occasional use of the SETOUT command to
Reset / unreset the DIM detectors and as a background refresh of digital outputs.

SETOUT commands to set changed digital outputs will be interspersed between polls, with
no request to return data.

GLOBADR commands are used to find all devices during a “Learn” initiated by the MX4428
and “Diagnostic Pollscan” initiated by the MX4428 or MXP diagnostic terminal.

(Refer to the “NOSEx SPECIFICATION” document for more details of the above
commands.)

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