# ISA Certified Automation Professional (CAP) program

Certified Automation Professionals (CAPs) are responsible for the direction, design, and deployment of systems and equipment for manufacturing and control systems.

## CAP question

A set of new, 4-20mA gage pressure transmitters has been wired to an analog input card in an existing PLC system, and you are tasked with scaling the raw input values in the PLC logic. This analog card has the following characteristics:

• Unsigned, 14-bit analog data format
• Eight (8) channels, 0-20mA inputs
• Single-ended inputs
• No channel diagnostics
• Data stored internally in integer "counts," from 0 up to the maximum 14-bit value

After reviewing these specifications, you determine the correct equation to program into the PLC to determine the current process values from the new transmitters is (where Engineering Units Value at 20 mA = EU100% and Engineering Units Value at 4 mA = 0 psig):

a. Analog Value in Eng Units=[EU100%-(Raw Counts-3277)] ÷ 4096

b. Analog Value in Eng Units=[(Raw Counts-819) × EU100%] ÷ 6048

c. Analog Value in Eng Units=[(Raw Counts-3277) × EU100%] ÷ 13106

d. Analog Value in Eng Units=[(Raw Counts+1637) ÷ EU100%] × 16384