Solution Cases [case-018]Improving the accuracy of detecting lamp disconnection

Problem

Our lamp annealing system for small-scale production was developed based on the concept of miniaturizing its dimensions.

For detecting lamp disconnection, relay circuit is used usually, but our euipment adopted the system using electric current value to meet the concept above instead of adding relays for each lamps. If electric current value while lamps generate heat is lower than threshold value, the system recognizes it as disconnection of lamp.

But the number of threshold value that operator can set is only one. Therefore, it could happen that lamp disconnection is not detected in some cases even though lamp(s) is(are) disconnected in fact, because electric current value is higher than threshold value depending on recipes.

Note: The function of detecting lamp disconnection is installed not standardly but optionaly.

Solution

By modification of software,

• Increase the number of threshold value operator can set
• Enable suitable threshold values to be set according to lamp output that changes from the start of heat treatment to the end of them.

Results

Lamp disconnection during heat treatment can be detected certainly at any lamp output.