I have a Labview program which sends 4-20ma current signal through a ni usb device to control the speed of a motor by controlling a sew eurodrive MOVIDRIVE ® MDX60B / 61B. Here is the data sheet of MOVIDRIVE:https://download.sew-eurodrive.com/download/pdf/16837614.pdf. PAGE 60 shows the layout of signal terminals. On the actual device, the input terminals are just two normal terminals,nothing special.
Originally, this motor is controlled by manually pushing some physical buttons on a device. The device is just some kind of signal generator that generats 4-20ma current signal.
The MOVIDRIVE ® MDX60B / 61B is set to accept 4-20ma current signal as control input.
So how can I switch between the two control signals (1.from labview, 2. from the device) so that there won't be any gap between the switch? I want to accomplish this because if the control signal drops to 0 at some point, the driver may get damaged. Since these equipment (both the movidrive and the motor) is really expensive and important, I can't risk damaging them by placing a switch in the circuit and just switch between the signals. Any advice is much appreciated!