ian.smith7
Member
Hi all
I have a 3 digit BCD thumbwheel that inputs figures into a 16 bit input module on a SLC502 plc. Only 12 bits of the input module are connected to the BCD inputs leaving inputs 12 to 15 unused. The FRD funtion directly addresses the input word meaning that the spare inputs are actually used. They are the only spare inputs on the plc and I would like to use them.
My idea is to use a masked move function to transfer the 12 used bits of the input word to a data register and then apply the FRD function to this register. This would then allow me to use the remaining 4 bits as ordinary Inputs.
Will this work and is it a reasonable/sensible thing to do. I do not want anything unexpected to cause problems.
my other options are to swop a 16 point input card for a 32 point or change the base from a 7 to 10 slot to add another input card.
any advice
cheers ian smith
I have a 3 digit BCD thumbwheel that inputs figures into a 16 bit input module on a SLC502 plc. Only 12 bits of the input module are connected to the BCD inputs leaving inputs 12 to 15 unused. The FRD funtion directly addresses the input word meaning that the spare inputs are actually used. They are the only spare inputs on the plc and I would like to use them.
My idea is to use a masked move function to transfer the 12 used bits of the input word to a data register and then apply the FRD function to this register. This would then allow me to use the remaining 4 bits as ordinary Inputs.
Will this work and is it a reasonable/sensible thing to do. I do not want anything unexpected to cause problems.
my other options are to swop a 16 point input card for a 32 point or change the base from a 7 to 10 slot to add another input card.
any advice
cheers ian smith
