Scale Function on MicroLogix 1200

[shayne]

Just a quick question regarding the SCALE function available on RS500. I was trained on RS5 and was taught to use block transfers for analog conversions. Apparently these are not used in RS500, so here is my question: is the SCALE function used for analog conversions exclusively or is there another function that was added to replace the block transfers?

 

[Allen Nelson]

You used Block Transfers for scaling, huh? While you certainly COULD do it that way, your data was limited to -9999 to +9999 (four digit signed BCD) if I remember correctly.

Most people use the BTR to get a raw 0-4095, and then an FAL to convert it to engineering units.

The SLC (and micrologix) work differently - the raw analog (3277-16383 instead of 0-4095, depending on the signal) come directly into the I/O image table, so no BTW/BTR is needed.

The scale functions (SCL and SCP) can be used anywhere you need to convert from one linear scale to another (you could use them to convert ºF to ºC, for example), but are typically used to convert the raw analog inputs to engineering units.

 

[shayne]

Thank You, as a non-fan of block transfers, that's what I was hoping to hear.

Cheers!