Rockwell Automation 1760-xxxx Pico GFX-70 Controllers User Manual - Manual (Page 65)

Publication 1760-UM002B-EN-P - March 2005
Installation 2-31
If inductive loads are not suppressed, the following applies:
Several inductive loads should not be switched off simultaneously to avoid
overheating the driver blocks in the worst possible case. If in the event of an
emergency stop the +24V dc power supply is to be switched off by means of a
contact, and if this would mean switching off more than one controlled output
with an inductive load, then you must provide suppressor circuits for these
loads (see the following diagrams).
Figure 2.37 Inductivity with suppressor circuit
Short-Circuit and Overload Behavior
Should a short circuit or overload occur on a transistor output, this output will
switch off. The output will switch on up to maximum temperature after the
cooling time has elapsed. This time depends on the ambient temperature and
the current involved. If the fault condition persists, the output will keep
switching off and on until the fault is corrected or until the power supply is
switched off. (See Monitoring of Short-Circuit and Overload with 1760-IB12XOB8
on page 8-7).
ATTENTION
Outputs may only be connected in parallel within a group
(Q1 to Q4 or Q5 to Q8, S1 to S4 or S5 to S8), such as Q1
and Q3 or Q5, Q7 and Q8. Outputs connected in parallel
must be switched at the same time.
ATTENTION
Please note the following when switching off inductive
loads:
Suppressed inductive loads cause less interference in the
entire electrical system. For optimum suppression the
suppressor circuits are best connected directly in the
proximity of the inductive load.
+ 24 V H
Q., S.
U
emax
< U
Z
< 33 V
0 V H
Q., S.