[Indirect addressing in RSL5K]

One way to get around this is: 1. Create dummy variables to pass to function block routine. 2. Jump to routine passing indirectly addressed variables as parameters. 3. Return result. Example attached fbd.ACD

[Wet Bulb Temperature Calculation]

I have outdoor temperature and relative humidity transmitters that are inputs in a Controllogix PLC. I need Wet Bulb Temperature to determine how to control Cooling Tower/ heat exchanger bypass valves. Ranges: Temp -20 to 120 deg F RH = 0 to 100% Does Anyone know the formula for calculating Wet Bulb Temp. from Dry Bulb Temp. and Relative Humidity???

[CRC Computation in PLC]

Ken, I could not find the Modbus example. What is the title? Thanks!!

[CRC Computation in PLC]

I'm working on a project where I need to compute a CRC value for a group of bytes recieved from a serial device. The serial device sends the CRC value as a part of the string. I need to compute the CRC in the PLC and compare to the recieved CRC for a pass/fail signal. The protocol uses CRC16-CCITT to compute the CRC. I'm using an Allen-Bradley Compactlogix PLC to recieve the data. Any information that would help will be appreciated!!!