We had an enquiry from a customer who needed to convert a 4~20mA DC signal into a frequency output – for example, to feed a legacy frequency counter or a PLC input that only accepts pulse signals. The ADtek MT-DF was built for this, and this particular listing, MT-DF1-A5-PN-V05-A2, is a specific pre-configured build. Before we go further though, we need to flag that ADtek has phased out the MT-DF entirely.
This looks simple, but the MT-DF’s part number encodes a lot. Based on the order code, this configuration is: single output (1), input range 4~20mA (A5), output range programmable across 8 ranges from 0~78.1Hz up to 0~10KHz – you specify the exact range – with output mode of voltage pulse at 5Vp, and AC230V auxiliary power (A2). Since the model is discontinued, any unit we can source would be from remaining stock, not a fresh production run.
In actual application, the MT-DF supported 4 popular input ranges and 8 output ranges programmable by dip switch, with dual isolated output available as an option. It plugged into the same 8-pin socket as the rest of ADtek’s MT series.
From our experience, before we quote this, we would normally check whether you specifically need this exact discontinued configuration, or whether an alternative ADtek frequency conditioner (such as the ST-RL in the current ST series) could do the job instead with full manufacturer support. Hope this helps.




