Can PLC5 N file hold decimal number?

I have a vibration transmitters, its scale is 0-1 inches/second for 4-20mA, it's Hi Hi SD is 0.6"/s. In the plc5 1771-IFE, it use BTR to read all the channel to N file. Does I need to expand RawMax in IO channel to 10(maybe) in order to hold 0.6( it become 6)in N files. Thanks.

wilsonzhu said:

I have a vibration transmitters, its scale is 0-1 inches/second for 4-20mA, it's Hi Hi SD is 0.6"/s. In the plc5 1771-IFE, it use BTR to read all the channel to N file. Does I need to expand RawMax in IO channel to 10(maybe) in order to hold 0.6( it become 6)in N files. Thanks.

Click to expand...

Yep

Hi Robertmee, do you mean expanding RawMax is th way to this sutuation. do it affect the field transmitter?

Greetings wilsonzhu ...

I'm not 100% sure that we're understanding your question ...

first of all, let's nail down one BIG idea ...

you can NOT store a decimal/fraction in an N-type location ...

going further ... in MOST applications, the IFE card gives a signal of 4095 when the input is 20 milliamps ... that is USUALLY the best way to bring the raw signal in from the field transmitter ...

THEN ...

once the signal has been brought into the processor (at an INTEGER location) we normally do the scaling with ladder logic instructions ... in your application, the scaled value probably needs to be stored in a FLOATING POINT (F8:X) location ... you CAN store a decimal/fraction in one of those ...

specific idea: even though the IFE CAN do onboard scaling, that's NOT the way we normally do things ... if I understand your question correctly, you're limiting the resolution of the module's signal ...

I this case, if I enlarge the RawMax to 100, does it affect the field transimmiter, because its scale is 0-1 inches/second. so in the program, I can use 60 instead of 0.6 inch/second(Hi HI Alarm setpoint).

wilsonzhu,
You can do as you subjest ( it does not effect the field transmitter), but thats not the standard way to do it ( you will lose resolution).
Reread Ron's post again. Then see example below.

Thank you Mickey, you are so helpful.

Don't forget to use the decimal points when you do the math, otherwise you will not come up the correct answer.