| 摘要 |
PROBLEM TO BE SOLVED: To surely detect the disconnection of each heater at low cost by a method wherein each normal heater current value of each heater of an injection cylinder is memorized in advance and the current value of each heater under the condition that the heater is forcibly turned on for a short period of time is compared with each memorized normal heater current value. SOLUTION: In a heater feeding part 3, three current sensors 4 are provided. Temperature sensors 5 and electromagnetic contactors 2 are connected to a cylinder temperature controlling device 6. Further, by measuring current values under the condition that a teaching signal A is inputted in the heater current measuring and controlling part 9 in the cylinder temperature controlling device 6, normal heater current values are obtained and stored in a memory 8. In order to carry out the heater temperature controlling of a molder, one heater circuit is forcibly turned on for the period of time required for measuring a heater current, the resultant current value is compared with the normal heater current value in the memory 8. If the result of comparison does not lie within the range of allowable value, the disconnection of the heater 1 of that circuit is decided, resulting in outputting a heater disconnection alarm signal B.
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