Siemens S5-135U/155U appendix Resetting, Control Line, Messages

Monitoring Module

Control Line	A control line fault (R/W) occurs if
Faults	± the write signal (MEMW/) and the read signal (MEMR/) are active
	simultaneously,
	± the acknowledgement signal (RDY/) is active without a (MEMW/) or
	(MEMR/) signal and
	± the address line 'peripheral memory' (PESP') has not changed from
	status ª1º to ª0.º
	Evaluation of the control signal (PESP') can be turned off with the S5/7
	switch. If the module is used in a programmable controller into which only
	I/O modules may be inserted (i.e. no memory modules or CPs), this switch
	must always be turned off. In this configuration, only I/O accesses to the bus
	are performed and the PESP` signal always has the status ª1.º It should also
	be turned off when using the IM 301, IM 302 1), IM 304 and IM 308
	interface modules for expansion units since a permanent PESP` signal can be
	applied to them.
BASP	If a command output inhibit (BASP) is active, the ªBASPº LED is lit.
Messages	If one or more faults occur, the corresponding LEDs are lit, the relay contact
	commutes and the module no longer acknowledges with the RDY/ signal.
	This timeout can be suppressed by opening the S5/8 switch.

10.1.5Resetting

There are several ways of resetting the module:

±CPKL/ signal = ª1º (when the PLC is switched on);

±Trailing edge of the BASP signal (during startup of the PLC or following return of the load voltage);

±Applying 24 V to the front connector X4 between connections 4 (RESET input) and 6 (L-);

±Linking connections 4 (RESET input) and 5 (L+) with connector X4.

1)In the S5-115U, the monitoring module cannot be used together with the IM 302 / 311 link.

System Manual	10-5
C79000-G8576-C199-06