I'm from Alberta too, and by I/P he means Current(I) to Pressure(P) Transducer. FBC and DDT are both shortcuts to supervise the status of bits in a word or words. Use the long way if the processor doesn't support them. What processor are you using and I might be able to help with instructions that you could use instead. Otherwise you can use EQU, MVM, etc. Also, an I/P is not a discrete switch, but an analog device, so you should be more specific in your question. Remember Dan, these are PLC experts, not Oil & Gas Process experts.