Honeywell QS7800B ユーザーズマニュアル

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QS7800B NETWORK INTERFACE CONTROLBUS™ MODULE FOR MULTI-DROPPING 7800 SERIES RELAY MODULES
65-0227—2
6
BUILDING A MULTI-DROP NETWORK
Guidelines
The subnetwork addressing in the Q7700 Network Interface 
Unit (NIU) is not contiguous. It is divided into two blocks, 
containing 198 and 24 addresses, respectively. A maximum 
multi-drop configuration would include 222 subnetworks (198 
plus 24) on a single Q7700 NIU. Because the 24 subnetworks 
are not contiguous, connect them to a separate Q7700 NIU 
slot.
One QS7800B ControlBus™ Module card  supports up to 31 
multi-drop subnetworks without using an RS-485 repeater. If 
an RS-485 repeater is used, up to 61 multi-drop subnetworks 
can be supported by one QS7800B card. The RS-485 
repeater must be installed between the 30th and 31st 
subnetwork.
Each subnetwork includes one 7800 SERIES controller with 
or without an S7800 Keyboard Display Module and/or an 
S7830 Expanded Annunciator. An S7810B1007 Multi-Drop 
Switch Module is required in each subnetwork. See Fig. 6 for 
wiring information. 
Subnetworks can be spread evenly (balanced) across the NIU 
slots. This will help to speed communications.
It is recommended that the multi-drop network be built starting 
with slot number 1 of the NIU, according to the guidelines 
above.
Record the serial number and physical location of each 
S7810B Multi-Drop Switch. This data will be useful when 
commissioning the ZM7850 Combustion System Manager 
(CSM) software. (Reference CSM manual, form 65-0102, for 
CSM commissioning.)
Examples
Network with  Maximum of 198 Subnetworks:
The open NIU slots can be used for other QS7800 ControlBus™ Module Cards.
Network with  Maximum of 222 Subnetworks:
NOTE:
For networks that have more than 198 subnetworks, 
the last NIU card slot must have the 199th through 
222nd subnetwork attached to it.
The open NIU slot can be used for other QS7800 ControlBus™ Module Cards.
NIU Slot Numbers
1
2
3
4
5
6
Total
Number of Subnetworks
61
61
61
15
Open
Open
198
Subnetworks Balanced
33
33
33
33
33
33
198
NIU Slot Numbers
1
2
3
4
5
6
Total
Number of Subnetworks
61
61
61
15
24
Open
222
Subnetworks Balanced
40
40
40
39
39
24
222