Honeywell 7800 Manuel D’Utilisation

3

65-0228—3

Canadian EMI: This digital apparatus does not exceed the 

Class A limits for radio noise emission from digital apparatus 

set out in the Radio Interference Regulations of the Canadian 

Department of Communications.

Le présent appareil numérique n’émet pas de bruits 

radioélectriques dépassant les limites applicables aux 

appareils numériques de la Classe A prescrites dans le 

Règlement sur le brouillage radioeléctrique édicté par le 

ministère des Communications du Canada.

Install the S7810B where the relative humidity never reaches 

the saturation point. The S7810B is designed to operate in a 

maximum humidity environment of 85 percent relative humidity 

continuous, noncondensing moisture.

The S7810B is not designed to be weather-tight. When 

installed outdoors, protect the S7810B with an approved 

weather-tight enclosure.

Do not install the S7810B where it could be subjected to 

vibration in excess of 0.5G continuous maximum vibration.

1. Align the two ears of the Multi-Drop Switch Module with 

the two mating slots on the 7800 SERIES Relay Module.

2. Insert the two interlocking ears into the two mating slots 

and, with a hinge action, push on the lower corners of 

the Multi-Drop Switch Module to secure it to the 7800 

SERIES Relay Module.

1. Refer to Fig. 2 for proper wiring.

2. All wiring must comply with all applicable electrical 

codes, ordinances and regulations.

3. Recommended wiring size and type:

a. For ControlBus™ communications, use 22 AWG, 

3-wire shielded cable (Belden part number 8723 or 

equivalent).

b. For 13 Vdc and remote reset switch operation, use 

22 AWG wire insulated for voltages and 

temperatures in the application. Suggested wire 

types include TW (60°C), THW (75°C) and THHN 

(90°C) Terminal identification numbers and letters 

shown in Table 1.

4. Wire routing:

a. Do not route the ControlBusª cable in conduit with 

line voltage circuits.

b. Do not route the ControlBusª cable close to the 

ignition transformers.

c. Route the ControlBusª cable outside of conduit if 

properly supported and protected from damage.

d. Route the ControlBusª cable so that all devices are 

connected in a daisy chain configuration. See Fig. 3.

5. Maximum wire lengths:

a. RS-485 Communications bus, 4000 feet 

(1219 meters).

b. Remote reset switch, 1000 feet (305 meters).

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.

One QS7800B ControlBusª 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 subnetworks.

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. 3 for wiring 

information. 

Subnetworks can be spread evenly (balanced) across the NIU 

slots to improve speed of communications.

It is recommended that the multi-drop network be built starting 

with slot number 1 of the NIU, subject to the above guidelines.

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. Refer to CSM manual, form 65-0102, for CSM 

commissioning.

Local Bus Data +

1

None

Local Bus Data -

2

None

Common

• Local Bus Common

• +13 Vdc Common

• Remote Reset Common

3

None

+13 Vdc

4

None

Remote Reset

5

None

Multi-Drop Bus Common

6

c

Multi-Drop Bus Data +

7

a

Multi-Drop Bus Data -

8

b