COTRUST CTH200 Series User Manual

Appendix
270
H.3.3 Diagnosis
Diagnose PROFIBUS DP master/slave network through LED status, STEP 7 fault information
and specific programming diagnosis.
Diagnose by SM 277B
The LED status for diagnosing SM277B can provide diagnostic information about connection
with the main station and self-diagnosis information of SM277B firmware.
After connecting SM 277B power supply, the LED indicator marked "ON" (green) light up.
If the BF and SF LED remain off, SM 277B will function normally.
If the BF or SF LED lights up, indicate an error in the extension module, address setting over
range, wiring, or main program configuration.
Function of EM277B LED:
LED
Color
Description
ON
Green
Indicator lights on when SM277B power on, controlled by
SM277B hardware
SF(system failure)
Red
If SM 277B find expansion module fault or address
setting over range, the LED light up
BF(bus failure)
Red
Flicker when no DP exchange with master station
If main system run without fault, bellows are the possible fault reasons:
 STEP 7 hardware configuration didn’t match completely with equipment in network. You
need to change the hardware configuration and download it to the CPU of DP master.
 STEP 7 configure wrong parameter
 The address STEP7 configured is different with SM277B actual PROFIBUS address, or
SM277B actual PROFIBUS address set as 126 127(invalid address). If the SM277B actual
address is correct, change the PROFIBUS address of the slave station device in STEP 7
and re-download the configuration to CPU of DP master station. If the actual address of
SM277B is wrong, change it, after that SM277B needs to be cut off and re-energized.
 Not set the PROFIBUS network terminal resistance correctly. Dial "ON" if you are at the last
node in the network, otherwise "OFF".
 PROFIBUS wiring error or PROFIBUS cable damaged. Check wiring and cables to make
sure they are correct.
Diagnose by STEP7
【Read diagnosis information in HW-Config】
For all SIMATIC S7/M7 series modules, S7 diagnosis can be called. For the base unit and I/O
modules, the structure of S7 diagnostics is the same. To make the diagnosis in STEP 7, read the
diagnostic buffer of the main station device or SM 277B.
【Confirm fault】
Confirm faults in HW-Config due to steps below:

COTRUST CTH200 Series Specifications

General

Brand	COTRUST
Model	CTH200 Series
Category	Controller
Language	English