Rs-232 Switch Panel Operation; Redundancy Wiring Diagrams - GE D20MX User Manual

To set up a redundant
system

RS-232 switch panel operation

To manually operate
the RS-232 switch
panel

Redundancy wiring diagrams

50
It is recommended that you install and configure one standalone D20 unit to ensure that
your configuration is valid and that device communications are operating properly. Once
this is done, proceed with the installation of the redundant system.
1. Mount the D20 units in a rack and connect power and ground.
2. Mount the RS-232 switch panel.
3. Plug the connector of watchdog cable A (GE part number 977-0160) to serial
connector COM 6 on the first D20 (CCU A).
4. Connect the bare leads of watchdog cable A to TB1 (position 6-8) on the RS-232 switch
panel.
5. Plug the connector of watchdog cable B (GE part number 977-0160) to serial
connector COM 6 on the second D20 (CCU B).
6. Connect the bare leads of watchdog cable B to TB1 (position 14-16) on the RS-232
switch panel.
7. Connect the bare leads of both watchdog cables to TB1 on the RS-232 switch panel
and the DB9 serial connector to either P1 or P9.
8. Connect one end of the ping cable to the first D20 and the other end to the second
D20. This ping cable must be connected to the same serial port number on both units.
9. Use standard RS-232 cables (GE part number 977-0121) to connect the D20 serial
communication ports to the serial ports on the RS-232 switch panel. P1 through P8 are
connected to the first D20, P9 through P16 are connected to the second D20.
Connections from the switch panel to both D20 units should be made in the same
order. For example, if P1 is connected to port 3 on the first D20, P9 should also be
connected to port 3 on the second D20.
10. Connect field devices to J1 through J8 on the RS-232 switch panel.
The RS2-32 switch panel has two sets of indicator LEDS:
• PWR A/PWR B: When lit, power and communications are received from the connected
units. Normally, both LEDs are lit.
• CCU A/CCU B: Normally, one LED is lit, indicating which unit is active.
The active/standby switch on the front of the RS-232 switch panel is used to:
• Restore a previously failed unit to active status once it has been repaired.
• Manually force a unit to active status so that routine maintenance can be performed
on the other unit.
1. Pull the active/standby switch straight out to release it from the locked position.
2. Switch it up to make unit A active or down to make unit B active.
The CCU A/CCU B LED indicator indicates which unit has been activated.
Figure 22 illustrates how to wire the D20MX units and RS-232 switch panels to enable
system redundancy:
The D20MX watchdog (control) port, heartbeat (ping) port, and serial port assignments are
software configurable. Refer to the D2x Configuration Guides.
CHAPTER 3: CONNECTING TO DEVICES AND NETWORKS
GENERAL D20MX HARDWARE USER'S MANUAL