38 Second-Generation Channel Interface Processor (CIP2) Installation and Configuration
CIP2 Hardware Installation
Step 11 It is also possible to connect the PCA to the host or mainframe using the straight-through
cable (CAB-PCA-S) as shown in Figure 23.
This connection technique uses the Y cable and eliminates the requirement for the VA and
VB cables from the host and to the next control unit, respectively. A straight-through
cable can also be used from the Y cable to the next control unit; however, if no control
unit exists, use a terminator.
Figure 23 Connecting the PCA and Host Using the Y Cable and Straight-Through Cable (CAB-PCA-S)
Caution
To prevent damaging the PCA connector on the CIP2, by unintentionally disconnecting
the Y cable from the PCA connector, make sure you provide adequate strain relief for the heavy bus
and tag cables that attach to the PCA.
Detaching the Y Cable from the PCA
To properly detach a Y cable from the PCA, use the following procedure.
Caution To reduce the potential for problems, you should have an authorized service representative
or other qualified service person perform the following procedure. To prevent hardware problems
with your host processor, all the channel connections must be tight. A loose connection can cause
the host processor or its channel to halt. Every cable must be tightly seated in its mating connector.
Step 1 Have the system operator vary offline all addresses assigned to the PCA. For instructions
on how to vary addresses offline, refer to the documentation for your mainframe
operating system.
Step 2 Place the select/bypass switch on the PCA connector in bypass mode. (See Figure 15 on
page 28.)
To allow the propagation of channel signals to downstream control units while the PCA
cable is disconnected, leave this switch in bypass mode.
Caution If the select/bypass switch is in select mode when the PCA connector is removed, other
devices on the channel and the mainframe operating system might not operate properly.
0
Single PCA
H2481
To host or mainframe
(male)
Straight-through
cable
From host or mainframe
(male, dark grey or black)
PCA connector
To next control
unit or terminator
(female, light grey)
1
