Despatch Protocol Manager with Protocol 3 and Protocol Plus - Manual (Page 55)

Protocol Manager Instruction Manual A PPENDICES
Version 1 55
Copyright © 2013 by Despatch Industries.
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6.1.4. Connecting Controllers to a Communications Host PC
6.1.4.1. Overview of Networking Multiple Protocol Plus Controllers
The host PC must have its assigned RS-232 COM port connected to a RS-422/RS-485 bi-
directional adapter, for example a “B&B Electronics” adapter. These P/Ns provide the adapter,
power supply and PC-to-adapter serial cable. The following wiring description refers specifically
to the B&B device, but may be applied to acceptable substitute devices.
The Protocol Plus controller’s optional communication card should be configured for RS-422A 4-
wire connection. Set the dipswitches and jumpers on the adapter to match the communication
from the host PC RS-232 COM port to the adapter. Wiring from the B&B adapter’s RS-422A
RS-485 terminals is daisy-chained to each of the Protocol Plus controllers. Connect the power
supply pigtail leads from the adapter wall mount transformer into the +12V and GND on the
adapter. Plug the transformer into a standard 120V / 60 Hz supply outlet.
Note that the communication ready ovens are supplied with two DB9 network ports;
“Communication In” and “Communication Out.”
For Shorter Networking Runs
Standard serial communication rated cables are available in a variety of lengths. Contact
Despatch Service for more information (see Section 1.2).
For Longer Network Runs
RS-422A/RS-485A cables typically consist of three individually shielded twisted pairs:

One pair transmits data from the host PC to the ovens

One pair transmits data from the ovens to the host PC

One conductor from the third pair is the signal common

The remaining conductor of the third pair is unused.
Cable such as Belden type 9843 should be used.
The network requires a cable breakout junction box near each oven. 120 ohm terminating
resistors must be installed at each end of the RS-422/RS-485 network (see Figure 48 for a

If the ovens purchased were not supplied with communication
options, order additional components (add-on Protocol Plus
communication board, internal cabling, DB9 external cable
connections) to make the ovens communication-ready. Order
components required to network two ovens to a host PC.
Contact Despatch Service for more information (see Section
1.2).