We call this a SIGNAL SPLITTER - SSP235. A four-way compact (22.5mm) Isolator powered by flexible 8-60VDC supply.
A recent design upgrade has added an incredible scope of flexibility. The input can now be coding plug selected for 8 standard process signals and both outputs are also coding plug selectable for 6 standard process signals each, a total of 288 combinations! Just with one model to keep in stock.
The SSP235 can support a 4-20mA Loop Powered transmitter as the input, by coding plug selected 20VDC isolated loop supply. Response time can be set to 5ms (fast) or 500ms (standard)
So who would use such a thing? Well there are an ever-increasing number of sensors and types of signals in today's process control environment. The process data might be needed at several receiving instruments or even systems. And we all know what happens when you run a 4-20mA signal in series to all sorts of devices, often being referenced to whatever the local earth might be.
So you can imagine how simple it is when you do not have to study each piece of equipment before the wiring diagram is drawn up.
Applications
You might have a 4-20mA loop powered Pressure Transmitter in the field. This pressure signal is needed at the PLC's 4-20mA input and also for the data acquisition system requiring 0-10VDC
Range Splitting the 4-20mA signal is to go to two control valves. Valve 1 needs 4-20mA for 4-12mA and valve 2 needs 4-20mA for 12-20mA all done with the SSP235.
Sometimes you run out of " Loop Drive" when the 4-20mA loops around to many instruments. The outputs from SSP235 effectively increase the loop drive to 2000 Ohm (2 x 20V drive)
