Honeywell HA71, Technical Manual

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HA71 Digital Gas Controller
Revision 3 (04/08)
HA71 Technical Manual 5-8
24 Hour Trend Database:
The 24 hour MAX, MIN and AVERAGE trend data may be retrieved over the Modbus
®
serial interface. Each channel consists of 240 MAX,
MIN and AVERAGE values, or, one value for every 1/10 hour (6 minutes). Since there are 16 channels this database equals 3,840 registers
in addresses 33017-36857. Due to the large size, MAX, MIN or AVERAGE values may only be retrieved one at a time. To improve bandwidth
the master may retrieve the database in blocks of 120 registers at a time (one half of a channel’s data). The C1 only updates these 3,840
registers upon receiving an update command from the Modbus
® master.
Type Channel First Last Read FC Write FC Notes
Update MIN n/a 2065 n/a n/a 5 Moves 24 hour MIN data trend to trend data base
Update AVG. n/a 2066 n/a n/a 5 Moves 24 hour MIN data trend to trend data base
Update MAX n/a 2067 n/a n/a 5 Moves 24 hour AVG data trend to trend data base
This update requires several seconds. Therefore, a data ready register is available to notify the master upon completion.
Type Channel First Last Read FC Write FC Notes
MIN Ready n/a 12065 n/a 2 n/a 0 = data ready; 1 = update in progress
AVG. Ready n/a 12066 n/a 2 n/a 0 = data ready; 1 = update in progress
MAX Ready n/a 12067 n/a 2 n/a 0 = data ready; 1 = update in progress
Trend database registers
Type Channel First Last Read FC Write FC Notes
24 hr Trend 1-16 33017 36857 5 n/a Transfers 24 hour trend for MAX, MIN or AVG.