When using a contactor with a DC coil inside with STO, it is important to make a return way for the current from the coil when turningit off. The return way can be created by using a freewheel diode (or, alternatively, a 30 V or 50 V MOV for quicker response time) acrossthe coil. Typical contactors can be bought with this diode.9.6.3 Analog InputsNumber of analog inputs 2Terminal number 53 (201), 54 (202)Modes Voltage or currentMode select Switch A53 (S201) and switch A54 (S202)Voltage mode Switch A53 (S201)/A54 (S202) = OFF (U)Voltage level -10 V to +10 V (scaleable)Input resistance, Ri Approximately 10 kΩMaximum voltage ±20 VCurrent mode Switch A53 (S201)/A54 (S202) = ON (I)Current level 0/4 to 20 mA (scaleable)Input resistance, Ri Approximately 200 ΩMaximum current 30 mAResolution for analog inputs 10 bit (+ sign)Accuracy of analog inputs Maximum error 0.5% of full scaleBandwidth 100 HzThe analog inputs are galvanically isolated from the supply voltage (PELV) and other high-voltage terminals.MainsFunctionalisolationPELV isolationMotorDC-busHighvoltageControl+24 VRS4851837e30ba117.11Illustration 52: PELV Isolation9.6.4 Pulse/encoder InputsProgrammable pulse/encoder inputs 2/1Terminal number (pulse) 29 (1) , 33Terminal number (encoder) 32, 33 (2)Maximum frequency at terminals 29, 32, 33 110 kHz (Push-pull driven)Maximum frequency at terminals 29, 32, 33 5 kHz (Open collector)Maximum frequency at terminals 29, 32, 33 4 HzVoltage level See Digital Inputs.SpecificationsOperating Guide | VLT® AutomationDrive FC 302AQ275652476278en-000101 / 130R0709138 | Danfoss A/S © 2019.12
