6
without protection elements the unit has to be sent to the producer for repair.
- Overvoltage at the output may damage the power supply. Coming from reliable operation of the
units have been already made, those are not equipped with any OVP circuit. The OVP protection in
the case of an active load (DC motor) may be done by two external rapid diodes connected
according to following figure 4:
In the event of passive inductive resistor load (solenoid), there must be used a rapid diode D1 at
least. The adjustable thyristor crowbar protection against internally as well as externally caused
overvoltages may be delivered as an option or may be made by a customer qualified person. In
generally, it’s difficult to predict max. allowed overvoltage in the case of the continuously
controlled output voltage power supply. The 3V margin would be dangerous at 5V output for
powering a TTL logic and lower one could be able to trigger the thyristor crowbar under normal
operating condition due to a disturb noise.
- Avoid condensation inside the power supply, break-down could be the result. Condensation may
occur during a period when the power supply is switched off and the ambient temperature is low.
Always allow the power supply to dry before switching it on again.
- An aggressive enviroment with acid, salt, etc. can harm the electronic components, afterwards pc-
boards may be dissolved.
- Don’t remove top or bottom cover of the case under operating conditions. Dangerous voltage may
cause a serious injury.
CALIBRATION
When there is a suspicion of incorrect display reading value of current or voltage, only qualified
person may do a calibration.
First needs to be adjusted reference voltage 5V source by trimer R241 on the control unit. Then may
be adjusted correct voltage by trimer R301 and current by trimer R401. Both are placed on the display
unit.
Enclosure: Interface RS 232 instruction manual or Analogue interface instruction manual.
Fig.4
SPS1000
D2
D1
