In its most basic form, the PDW90 consists of field units (up to 32) that accept 4-20 mA signals and transmits them wirelessly to a base station. The primary advantage of this system is how simple and economical it is to get multiple signals (not just 4-20 mA, also discrete (digital) and Modbus) from where you have them to where you need them – all without having to run wires!
The wireless communication between the field units and the base station is bi-directional. That means you can send 4-20 mA, discrete and Modbus signals from the field units to the base station and also send completely different 4-20 mA, discrete and Modbus signals from the base station to the field units. For instance, the field unit could send a 4-20 mA signal to the base station corresponding to the level in a tank and the base station could send a 4-20 mA sig-nal to the field unit to control a valve.
Field units are also equipped with four digital I/O that can each be independently programmed as an input or an output. A Loss of Signal warning is also available by connecting devices to the G and LS screw terminals.
To indicate alarm situations in the field, the field unit can be equipped with an optional, field installable, two relays module. These relays are rated Form A (SPST) 5A and are controlled by the digital outputs on the base station.
The base stations are available in configurations for 2, 6, or 16 I/O slots for a variety of field installable I/O modules. The available I/O modules are:
- •Dual Analog Input
- •Dual Analog Output
- •Dual Relay Output
- •Four Digital I/O
The specified range between the base station and field units is 1 mile line-of-sight outdoor and 500 feet indoor and repeaters are available to extend the range. A low-cost wireless survey tool, Model PDA10, is available to test the signal strength of your application before you buy. And if the PDW90 system does not work in your application, you can return it for full credit!