Micromod Micro-DCI: 53MC5000 PLC AND PRINTER INTERFACES - Manual (Page 91)

7.6 FAULT ISOLATION AIDS
Table 7-5 summarizes information provided in this section and other sections of the book that can
be referenced as an aid to fault isolation.
Table 7-5. Fault Isolation Aids
Environmental/Power
See Table 1-1 for RS-232/485 ITB environmental and power specifications; see 53MC5000 PCS
Instruction Bulletin for PCS environmental and power specifications.
PCS Setup Errors
Setup Errors 1 through 4 (Table 7-2) - Violating memory map restrictions. Setup Errors 5 and 6 =
Invalid Function Code and Bad Write Command. Setup Error 10 = Scan Time at 0. PCS APB
Setup bytes (Table 7-1) - Should agree with the communication setup of the PLC system.
Scan Overrun Counter (Table 7-2 and Section 3.7) - Expand Scan Time if the count increases at
an unacceptable rate.
Communications
Proper cable fabrication between the RS-232/485 ITB and the PLC (Figure 7-2).
Communication Error and Error Count (Tables 7-3 and 7-4) - For checksum (Block Check
Character [BCC]) and bad message errors, the PCS does not use the data but will try again, for
example: if a checksum error occurs during the read, the PCS will perform the write in that Scan
Time and attempt another read the next Scan Time. If there are five consecutive read errors or
five consecutive write errors, the PCS causes a re-initialize sequence.
Possible PLC Problems
PLC Error Code and Error Count (Tables 7-3 and 7-4) - Convert decimal PLC Error Code to
hexadecimal using Appendix A and reference the Siemens PLC documentation for possible
explanation.
RS-232/485 ITB Activity Indicators
Inactivity from the XMT (CR13) and RCV (CR14) LEDs could indicate line problems, a hung
device, a misconfiguration between the PCS and PLC resulting from manual database alterations
made at either device, or just no DDI channel activity. Active indicators on the RS-232/485 ITB
do not necessarily mean error free operation, e.g., repeated PCS-PLC transactions attempted
with timeout errors.
Section 7. Siemens S5 Mode
SIEMENS
7-7