Question: I use two 1KF02 analog input module, provided separately for modules 1 and 2. Module configuration:
Module 1, the first four–channel configuration for current signals, four channel configuration for RTD Pt100; first six channel module 2 configuration for RTD Pt100, two vacant channel, STEP7 will disable it. Current signals by two–wire connection, PT100 wire connection, and are connected to the surge protector. M-interconnect on the module 1, module 2 M-on interconnection.
Now appears as follows:
1, a signal generator for my analog PT100 input, only one channel at a time, the rest of the RTD channel is disabled, normal; if one channel is activated and connected to the fixed resistor, while the channel signal generator doesn’t work, monitoring their PIW showed in the change between normal and 327,672.
2, connect the 10 RTD channel all resistors, fixed, normal, but as long as any one channel connected to the signal generator, the PIW channel values in between the normal and 327,672 beat. (Signal generator to determine is good)
Answer: this possible relationship with the 1KF mode, problem was caused by a signal generator, directly connected resistance test it.
Question: owner ill, really is the signal generator problem, not interference.
Today to get a morning, due to the new, but to turn to the technical staff, Siemens hotline, the technician asked concluded modules have no problem, the signal source may be used. Last I call to signal source manufacturers, is that victory brand, he to I explained has reasons, signal source simulation hot resistance output, just with circuit principle simulation output a resistance value, is not a entity resistance, need a constant of external incentive current; and PLC is individually scan the channel, that PLC cycle in all channel Zhijian switch, led received signal source of that channel kept to in pass, and broken Zhijian switch, is signal source of external incentive current in pass broken switch, So the channel kept switching between the normal and circuit breaker values. When only one channel, other channels are not active, the signal source, the excitation current is constant, channel value is normal.