4-20mA loop powered LVDT transducer amplifier

The RDP S7TW is a loop-powered LVDT transducer amplifier that uses a straightforward 2-wire, single floating supply interface (12V to 36V) to transform an LVDT's raw AC displacement signal into a typical 4-20mA output. It is enclosed in a die-cast aluminium shell that provides high environmental protection and electrical noise shielding, making it ideal for tough industrial or field environments. It is designed to install near to the transducer, enhancing the signal right at the source.

The amplifier has a wide gain range (2.5 to 333) with a signal input range of 0.03V to 4V, making it compatible with most LVDTs on the market, not just RDP's own range (a few RDP models require a free TM0202 modification). Simple trimpot controls make setup simple. A minimum LVDT input impedance of 130Ω is required, and the transducer excitation is 0.5V at 5kHz, drawing a maximum of 4mA.

In terms of performance, it provides ±0.05% F.S. linearity, low temperature drift (±0.005% F.S./°C zero, ±0.015% F.S./°C span), and a broad temperature range of -20°C to 85°C. It can accommodate cable glands ranging in size from 3.0mm to 6.5mm and weighs 550g.

Note: RDP specifically cautions against using the S7TW as a safety, emergency-stop, or feedback device in situations where a malfunction could result in harm, death, or damage to the equipment.