I was having a conversation with someone about powered inputs and on the topic I had remembered Circon UHC series had a jumper switch and they guy said with Distech you need to add the external resistor. I think XL800 modules need external resistor... so the question what do the other vendors do?
They are probably talking about converting a 0-20 mA signal to 0-5 volts (w/ 250 ohm resistor), or 0-10 volts (using a 500 ohm resistor). Companies like ALC can handle 0-20 mA inputs, while Novar cannot (need external resistor to convert to voltage).
Schnider Electric(TAC) needs resistor to convert 0-10v to 4-20ma.
CSI uses resitor to determind hte input value, these are built into the programmable boards.
Distech uses resistors for there 4-20ma input signal.
Distech also has jumper for output of 4-20ma or 0-10vdc
Circon older controllers need the resistors for conversion also.
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Kontrolphreak,
maybe I'm using the wrong term here. The inputs on all the newer (V3.22 and up) stuff use switches that are a bit larger than a typical dip, but I dont know what else to call them. On the switch, the installer can choose between 4-20, 10k, 5v and 10v.
I always setup my inputs for voltage and use an external resistor to convert - 4-20mA signals to 1-5VDC or 2-10VDC (depending on the controller). That way I can troublshoot down the line easier with a meter rather than having to do the stupid put your meter in series with the signal thing....Just my $.02
justjohnson - current remains the same over the entire circuit. go with 4-20 for distances. and there are meters that will read 4-20 without getting in series.
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