Rockwell Automation 1775-S4B,D17756.5.3 User Manual SCANNER/MSG HND - Manual (Page 12)

I/O ScannerĆMessage Handling Module
Chapter 2
2Ć3
Below the thumbwheel switch are four green LEDs labeled:
CH1
CH2
CH3
CH4
Each LED corresponds to one of the four I/O communication channels.
Each I/O channel can connect to a bulletin 1771 I/O chassis or a group of
chassis providing direct communication with the 1775-S4B scanner. Each
indicator has the following meanings:
If the LED is: Then:
On Proper communication exists between
1775ĆS4B scanner and the I/O chassis on the
corresponding I/O channel.
Flashing A fault exists on one or more of the I/O chassis
on the corresponding I/O channel.
Off No I/O chassis are connected to the
corresponding I/O channel.
Below the I/O channel indicators is a connector labeled BACKUP. This
connector is not used.
Below the backup connector is a 25-pin D-shell connector labeled CH5.
This connector provides communication with an RS-232-C device such as
a data terminal, a computer, or a printer. Refer to chapter 3 for installation
information.
Near the bottom of the 1775-S4B scanner is a Terminal Swing Arm (cat.
no. 1775-WA). This swing arm contains the connection terminals for
channels 1 to 4 which scan I/O chassis. We discuss cable connections for
the I/O communication channels in chapter 3.
2.1.3
I/O Channel Status
Indicators
2.1.4
Backup Connector
2.1.5
Channel 5 Connector
2.1.6
Terminal Swing Arm