Technical Manual &
Cabling Instructions
Page 41 / MAN000596
Internal Diagnostics
Epec Oy reserves all rights for improvements without prior notice
Epec Oy
Tiedekatu 6
FIN-60320 Seinäjoki
Postal address
PL/P.O.Box 194
FIN-60101 Seinäjoki,
Finland
Phone
+358-(0)20-7608 111
Fax
+358-(0)20-7608 110
Internet
www.epec.fi
13.2 + 5 V REF Diagnostics
The +5 V reference supply has two diagnostics checks:
• analog output voltage monitoring and
• dedicated digital fault-signal
Both can be used to indicate overload and overvoltage situations. The diagnostics are
independent from each other.
For fastest and most reliable error detection, it is recommended to use both
output voltage monitoring and fault-flag diagnostics to detect errors.
13.2.1 OVERLOAD
The diagnostics can detect overcurrent situation. The fault-signal is activated when excessive
current is taken from the output. The output current is regulated when internal current limit is
reached. The regulation current is always smaller than the limit. Current regulation causes the
output voltage to drop with increasing load. This can be detected, using the output voltage
monitoring feature, by setting a minimum (low) value limit for the output voltage.
With large enough loads, the output voltage drops to 0,1 V and the output current is limited to I
o-
sc
value to protect the output from overheating.
This is indicated by the fault-signal. The fault-signal is deactivated, when the error source is
removed by decreasing the load (and reducing the output current below I
o-sc
value ) or when the
output is turned off.
It is recommended to turn off the output when fault-signal becomes active.
13.2.2 OVERVOLTAGE
Overvoltage event caused by an external source can be detected by using a combination of the
diagnostic features. The fault-signal is activated when pin voltage goes above the fault-signal
overvoltage threshold level. If the output voltage monitoring value is above nominal and/or the
fault-signal is active, it can be determined that an external voltage source is connected to the
output pin.
The output pin is protected against external voltages, but it is not recommended to connect
external voltage sources to this pin.
In case of a limit violation, the output should be disabled as soon as possible. The
unit can handle short term errors, but long term (e.g. several hours) exposures
should be avoided with application/system design. Long term exposure to
overvoltage or overload can cause permanent damage to the unit.
To Next Page
Loading...