KEB COMBIVERT F4-C Applications Manual

Also see for COMBIVERT F4-C: Instruction manual

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5ANTRIEBSTECHNIK6 2 5KEB COMBIVERT F4-CName: Basis616.02.00Section PageDate© KEB Antriebstechnik, 1999All Rights reservedChapterFunctional DescriptionAnalog In- and Outputs6.2.4 Buffer Memory(An.22)In order to control various inverters with different frequencies via the analog output ofa PLC, an analog memory was implemented. It is adjustable with parameter An.22and controlled with a programmable digital input.For a better understanding, a short example follows:Five inverters (each operating one conveyor) shall be controlled by a PLC with ana-log setpoint values. Due to different values, a parallel control is out of question; forcost reasons, the same is true for a PLC with five analog outputs.Generally there are enough digital outputs at the PLC and we use them for releasingthe analog input of the inverter. (like a CS-signal in the digital technic) The analoginputs will parallely be switched to an analog output at the PLC. If the CS-signal isset, the inverter operates with the actual value. If the CS-signal is switched off, theinverter operates with the analog value, which was applied up to this point of time. Inthis way, e.g. all inverters together can be started up. If the first inverter has reachedhis setpoint value, the CS-signal is switched off for this inverter. If the next inverterhas reached his setpoint value, the CS-signal also will be switched off (and so on).Depending on the specific kind of operation, it is also possible to set each inverter tothe setpoint value seperately.S2S1PermanentBufferAn.22=1/2/16Direct ModeBuffer Modeprogr. digital input di.3...di.10 Value 11/12/13Analog value from input (set)Analog value from buffer (not set)An.22=4/8/32Buffer clean atPower offPicture 6.2.4 Principle of buffer memoryfrom inputfilterto thecharacteristicsamplifierComing from the input filter, the memory mode can be switched on with An. 22. If theprogrammable digital input will be set now (S1 closed;S2 open) the analog signal willdirectly be transmitted and parallely stored in the non-volatile memory. As soon asthe digital input will be switched off (S1 open; S2 closed), the inverter will continue tooperate with the value stored in the memory. In addition it can be determined withAn.22 whether the storage contents shall be conserved or cancelled.An.22 Function0 = off 1 = on Memory mode for ±REF0 = off 2 = on Memory mode for REF0 = off 4 = on Delete ±REF-memory when switching off0 = off 8 = on Delete REF-memory when switching off0 = off 16 = on memory mode for analog option0 = off 32 = on Delete memory for analog option when switching off0 = off 64 = on Simulation of analog Option by ±REF (s. picture 6.2.1)0 = off 128 = on Displays after input amplifier (s. picture 6.2.1)An.22 Analog-In-ModeThe sum of all „on“ values has tobe entered in An.22