Internet PLC Forum

General => Technical support => Topic started by: Andy on November 29, 2003, 06:59:09 AM

Title: Choosing ideal input Signals
Post by: Andy on November 29, 2003, 06:59:09 AM

We are looking for Probes etc. to attach to the MD888+ Super PLC. Now, we found a lot of different Input Signal types like 4-20mA, 1-5V,1-10V and much more. What are the best or lets say easiest Input Signals to handle with the PLC? What we see is that we may must be able to use the 4-20mA Signal for some Sensors (2Wire, at least 4x). Can you advise us? Thanks in advance

Andy

Title: Re: Choosing ideal input Signals
Post by: support on November 29, 2003, 11:41:45 PM

The easiest type of sensor to use it one that output 0-5V which can be connected directly to the PLC's analog input. Of course you need to ensure that if the sensor has its own power supply then the sensor's ground must be common with that of the PLC's 0V.

If your sensor output 4-20mA, you can convert the current into 1 to 5V voltage using a 250 Ohm resistor (read your installation guide for the wiring method). Both 2-wire and 4 wires types can be used.