Analog input: Monitoring does not detect some errors (corrected from V01.05.02)
Corrected from:
Servo inverter i950 FW: from V01.05.02.1788
Response of the new version:
The mentioned error cases are now detected and signaled accordingly via the status bits 10 and 11 in 0x2DA4:016. The internal shunt resistor is now deactivated when the maximum negative input current of -28mA is exceeded, so that it cannot be damaged.
What happens?
The monitoring of the analog inputs does not detect all cases of exceeding the specified limit values. When parameterized as voltage input, exceeding the maximum input voltage of +11V is not detected and accordingly status bit 11 in 0x2DA4:016 is not set. When parameterized as a current input, exceeding the maximum negative input current of -28mA (corresponding to approx. -7V) is not detected and accordingly status bit 10 in 0x2DA4:016 is not set. In this case, the shunt resistor for current measurement is also not switched off, which can lead to thermal overload and thus possibly to destruction of the shunt.
When does the behaviour occur?
Analog input parameterized as voltage input (0...10VDC [0] or -10...+10 VDC [3]) and an input voltage of <= +11V is applied.
Analog input parameterized as current input (4...20mA [4] or 0...20mA [5]) and the input voltage is less than the minimum voltage of -7V.
To protect the device, do not let the driving voltage for the input current drop below -7V, because the internally used shunt resistor can be damaged by negative measuring currents.
