Instruction Manual

Troubleshooting
Appendix B
B-3
Consult the following table to identify PLC communication problems.
Problem Cause What to do
PLC Communication Lost" message on the
PanelView 1200 terminal.
PLC controller is in Program or Remote Program
mode.
Change PLC controller to Run mode.
Cable problem. Check termination and cable pinout.
Incorrectly defined terminal as Last Chassis. Set Last Chassis to No for that rack assignment.
Rack assignments in the PanelView 1200
terminal and the PLC do not match.
Make sure rack assignments in the PLC
controller match those in the PanelView 1200
terminal.
Terminating resistor not installed properly. The terminating resistor must be installed at the
PLC and at the end of the link:
150W 1/2 watt resistor for 57.6 or 115.2 kbaud
82W 1/2 watt resistor for 230 kbaud
The PanelView 1200 terminal and Scanners
Remote I/O baud rate do not match.
Change the Remote I/O baud rate in the
PanelView 1200 terminal or the scanner so they
match.
PLC Communication Lost" message when
using the PanelView 1200 terminal with PLC5.
The PanelView 1200 terminal has been
assigned to multiple or partial racks when
firmware revision of PLC5 does not support
partial rack addressing.
Configure the PanelView 1200 terminal as a
single full rack.
Upgrade PLC5/15 to Series B Revision H or
later.
Upgrade PLC5/25 to Series A Revision D or
later.
PLC controller is not configured to recognize the
PanelView 1200 terminal's rack assignments.
Refer to your PLC5 User's Manual regarding
Auto Configuration.
Periodic PLC Communication Lost" when using
1772SD2 scanner with PLC2s.
Must use 1772SD2 scanner Rev. 3 or later.
Rapid blinking of PLC Communication Lost"
when using 1775S4A scanner with a PLC3.
Must use 1775S4A scanner series B or later.
PLC Communication Lost" when using SLC 500
1747SN Scanner Module.
The 1747SN Scanner Module is not properly
configured.
Refer to 1747RIO Scanner User's Manual
regarding Specialty I/O Configuration and how to
configure Mfiles and Gfiles.
Verify that the PanelView 1200 terminal and the
1747SN Scanner Module Remote I/O baud
rates are set the same.
Discrete I/O works but block transfer does not.
No PLC Communication Lost" message. Using
PLC5/15, partial rack addressing.
Must use PLC5/15 series B Rev. J or later.
Discrete I/O works but block transfer does not.
No PLC Communication Lost" message.
Block transfer assignments in the PanelView
1200 terminal do not match block transfer
instructions in PLC.
Make sure PLC block transfer instruction
parameters match the PanelView 1200
parameters.
PLC Controller rack fault on rack assigned to the
PanelView 1200 terminal.
Specified No for Last Chassis when the
PanelView 1200 terminal is the last chassis in
that rack.
Set Last chassis to Yes for that rack assignment.
PLC Communication Lost" message and rack
fault on rack assigned to the PanelView 1200
terminal.
Mismatched baud rate on the PanelView 1200
terminal and PLC controller.
Specify same baud rate for the PanelView 1200
terminal and PLC controller.
Multiple devices configured for the same rack
assignment.
Multiple remote I/O devices must have unique
rack assignments.
PLC Communication Problems