varistor check

Please I would like to know for my project some technical information
I want to make a varistor check and I noticed that it exists at beckhoff the EL3681 EtherCAT Terminal that allows the measurement of currents and voltages in the wide input range.
Is there one or more terminals with which I can use to send a certain voltage between 0 - 65 V and current between 0-2A and control? And measured the falling voltage again.
Or do they have any Possibility option I can use to realize this test? Because for this project I should send a certain voltage (0-65V) and certain current (0-2A) to the varistor and measure the fallen voltage again.
Do they have a solution for me?

Best regards

Thierrytft

We use the EL3692, which is designed to measure resistance (2 chan). It measures voltage drop at a single "test current". But, that test current changes w/ range setting. You can set different ranges from your PLC code, so might get several points on the dV vs mA curve that way to determine resistance vs dV (varistor = voltage-dependant resistor). But you want a more continuous curve and at higher dV and mA values. I recall the EL3692 is limited to 45 mA output and dV = 10 V.

I don't know of any Beckhoff modules which can source > 10 VDC, but the EL3681 "mulitmeter" module can read the 65 V and 2 A you need (1 module per task). A Beckhoff module could output a voltage signal (0-10 V) and an external linear amplifier increase that proportionally to 65 V. There are V to mA "coil drivers" used for hydraulics (Delta Computer, etc), but I recall only to 100 mA output. Alternative to the EL3681 is an external voltage attenuator and external current sensor, along with standard Beckhoff differential voltage input modules (ex. ELM3002-0000 ). For a custom attenuator board, look at Caddock attenuator "chips" (used in multimeters) or for a packaged board Dataforth SCM5B40. For current, a Kelvin shunt resistor (Emco, etc) usually has dV = 50 mV signal and come in many Amp ranges.

For a lab test stand, it might be easier to use an instrument such as a Keithley source-meter, if they have the range you need. They likely have I/O that can be read by the PLC or an HMI PC program.