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Can Siemens MM420 Inverter Output Current Hz with Voltage Signal
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Rt, or can only use the current signal, if possible, how to set the parameters
MM4 series converter can only output 0-20mA (4-20mA) current signal, but can not output voltage signal.
If the output voltage signal is needed, a 500 ohm high precision resistor should be connected in parallel to convert the current signal into the voltage signal, and then the 0-10V signal will be output.
It should be noted that the analog signal usually uses 0-20mA (or 4-20mA), but seldom 0-10V, because the resistance of the cable will divide voltage and cause transmission error when the distance is long. It is suggested that a 500 ohm parallel connection between analog input terminals can solve your problem. Of course, an input: 0-20mA, output: 0-10V signal isolator can also be installed, which is more standardized.
The analog output of MM4 series converter is unable to output the output frequency in the form of 0-20 mA (or 4-20 mA) if the output frequency is negative when the motor is reversed.
If it is necessary to output the frequency of the converter in both forward and reverse states in the form of 0-20 mA (or 4-20 mA), the following methods can be used:
Method 1. Setting parameter P0775 = 1.
Method 2. For the early products of MM4 series, because the software version is relatively low, you will not find the P0755 parameters. You need to enable the free function block to set parameters as follows:
The precondition of this method is P2200 = 0, P2800 = 1 (enabling free function block)
P2802 [8]= 1 (enable multiplier)
P2877 [0] = 21 (frequency as multiplier input 1)
P2877 [1] = 21 (frequency as multiplier input 2)
P2264 [0] = 2878 (multiplier output as feedback input)
P2270 = 1 (Square Root Processing for Feedback Input)
P0771 = 2272 (analog output is specified for **value)
Therefore, when the current frequency of the converter is negative, it is necessary to square the frequency first and then square it with the free function block, and then give the result of the square to P0771.
Method 3: MM420 converter has no free function block, so method 2 can only be used in MM430 and MM440. But how to control the part is Siemens S7-200, 200smart, S7-1200 PLC, you can also consider UUS communication mode, only through 14 and 15 terminals to read MM420 frequency, current, torque and other information.
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