Page 64 - Programmable Logic Controllers, Fifth Edition
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CHAPTER 2 PROBLEMS
1. A discrete 120 VAC output module is to be used to c. If the ambient temperature rating for an I/O
control a 230 VDC solenoid valve. Draw a diagram module is specified as 60°C, how much is this
showing how this could be accomplished using an expressed in degrees Fahrenheit?
interposing relay. 4. Create a five-digit code using the SLC 500 rack/
2. Assume a thermocouple, which supplies the input slot-based addressing format for each of the
to an analog input module, generates a linear volt- following:
age of from 20 to 50 mV when the temperature a. A pushbutton connected to terminal 5 of module
changes from 750 to 1250°F. How much voltage group 2 located on rack 1.
will be generated when the temperature of the b. A lamp connected to terminal 3 of module
thermocouple is at 1000°F? group 0 located on rack 2.
3. With reference to I/O module specifications: 5. Assume the triac of an AC discrete output module
a. If the ON-delay time of a given discrete input fails in the shorted state. How would this affect the
module is specified as 12 ms, how much is this device connected to this output?
expressed in seconds? 6. A personal computer is to be used to program sev-
b. If the output leakage current of a discrete output eral different PLCs from different manufacturers.
module is specified as 950 μA, how much is this What would be required?
expressed in amperes?
PLC Hardware Components Chapter 2 45
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