Siemens S7-300 Installation And Operating Manual page 135

Causes of the problem and corrective measures
The table below shows the possible causes of the problem and associated corrective
measures for the individual diagnostic messages of the SM 326, DO 8 x DC 24V/2A PM.
Table 8- 18
Diagnostic
message
Wire break
Short-circuit of
output to M, or
defective output
driver
Short circuit of
output to L+, or
defective output
driver
Short-circuit at the
load; or defective
output driver
Defective output
driver
Overtemperature at
output driver
External load
voltage missing
Fail-safe signal modules
Installation and Operating Manual, 01/2010, A5E00085586-10
Diagnostic messages and associated corrective measures for SM 326; DO 8 x DC
24V/2A PM
Error detection
General
General
General
General
General
General
General
8.5 SM 326; DO 8 x DC 24V/2A PM
Possible causes of the
problem
Wire break between the
module and actuator
Channel not connected (open)
or unused
Output overload
Short-circuit between the M
output and M of the module
power supply
Undervoltage at load voltage
supply
Defective output driver
Short-circuit between the
output and L+ of the module
power supply
Short-circuit between
channels which carry different
signals
Defective output driver
Short-circuit at the load
Defective module
Short-circuit at the output
Output overload
Internal fault at output driver
Supply voltage 1L+ of module
missing
Digital modules
Corrective measures
Restore the cable
connection
Disable the "Group
Diagnostics" for the
channel in the parameter
settings.
Eliminate the cause of
overload
Eliminate the short-
circuit. Reset the module
by cycling supply voltage
1L+ off/on
Check the load voltage
supply
Replace the module
Eliminate the short-
circuit
Module reset required
(supply voltage 1L+
off/on)
Eliminate the short-
circuit
Module reset required
(supply voltage 1L+
off/on)
Replace the module
Eliminate the short-
circuit; reset of module
required (supply voltage
1L+ off/on)
Replace the module
Eliminate the short-
circuit. Reset the module
by cycling supply voltage
1L+ off/on
Eliminate the cause of
overload
Replace the module
Connect 1L+
135