Lab 1 Sensor Census

Name

Partner(s)

Station #

Paired with station

Section

Date

0:00–0:10 instructor briefing — Parts A & B 0:10–1:05 bench work — Parts C–F 1:05–1:15 kit check-in and cleanup — Part G Part H take-home

Scored out of 100 Steps recorded, Parts C–F — 70 Check-offs, Part E — 10 Reflection, Part H — 10 Cleanup, Part G — 10

Lab rules — read before you move

Eye protection on for the entire session.
Every sensor comes from the cabinet and goes back to the cabinet. Your kit is signed out to your station and signed back in before you leave. A missing sensor is a lab that cannot run next week.
Six of the eight devices are yours alone. Two are shared with your paired station — stations pair up 1&2, 3&4, 5&6. Hand them over promptly; do not walk off with one the other team is mid-measurement on.
Report any damaged cable, cracked housing, or bent probe the moment you find it. You will not be blamed for reporting damage you discovered.

What is in the kit — count this at checkout

Six stations, six kits. The lab stocks enough of most sensor types for every station to have its own; two types are short, so those circulate between paired stations. When you record a device in Part D, mark S if it came in your own station kit and P if it is a shared item borrowed from your pair.

Inductive proximity barrel — two of these, different part numbers
Capacitive proximity barrel × 1
Through-beam photoelectric — emitter and receiver
Diffuse photoelectric, background suppression × 1
Ultrasonic proximity × 1
Shared: retroreflective photoelectric + corner-cube reflector
Shared: small diffuse photoelectric × 1
Patch leads and a corner-cube reflector card

Part A Field reference — what am I holding? briefing · read along

Use this to classify each device in your kit. The “tell” column is what distinguishes it on sight or with a quick, safe test.

Device	Senses	The tell	Typical output
Inductive proximity	Metal only, no contact	Barrel with a plain face; ignores your finger, trips on a wrench	discrete PNP/NPN
Capacitive proximity	Metal and non-metal	Similar barrel; trips on your finger, plastic, liquid	discrete PNP/NPN
Photoelectric — through-beam	Beam broken	Two separate units, emitter and receiver, facing each other	discrete PNP/NPN
Photoelectric — retroreflective	Beam broken	One unit plus a corner-cube reflector	discrete PNP/NPN
Photoelectric — diffuse	Light bounced off the target itself	One unit, no reflector; usually a sensitivity adjustment	discrete PNP/NPN
Diffuse, background suppression	Light bounced, but only inside a set range	Diffuse body with a distance setting; ignores the wall behind the target	discrete PNP/NPN
Ultrasonic	Distance, non-contact	Visible transducer face; works on clear and shiny targets that defeat photoelectrics	analog or discrete

Part B Sourcing, sinking, and the wire count briefing · read along

2-wire	Loop powered — the sensor sits in series with the load and has no separate supply leg.
3-wire	Brown = +24 V, Blue = 0 V, Black = signal. By far the most common discrete arrangement.
4-wire	Adds a second output — often a complementary NO/NC pair, sometimes a second setpoint. White is the second output.
PNP — sourcing	When active, the output supplies +24 V to the load. The load's other end returns to 0 V.
NPN — sinking	When active, the output pulls the load down to 0 V. The load's other end hangs on +24 V.

Decode it from the part number

Look closely at the part numbers in your kit. Several of them differ by only one or two characters — and that difference is not cosmetic. Two sensors that look physically identical may be opposite output types. Work out the manufacturer's convention from the kit itself, then confirm it against the datasheet. Record what you conclude in Part D, and say what evidence convinced you.

Part C Kit checkout 2 min

One team member signs the kit out. Count the contents against the list above before you start — if something is already missing, you want that on record now, not at the end. Log the shared items separately; they move between your station and your pair.

What	Signed out by	Time out	Contents complete?	If not, what is missing or damaged
Station kit #____
Shared items

Part D Sensor characterization 25 min · swap shared items at the halfway mark

One row per device. Copy part numbers exactly, including every dash and suffix — the suffix is usually what encodes the output type. Write “illegible” rather than guessing. For Output write PNP, NPN, or analog. For Evidence say how you know — part number suffix, datasheet, printed on housing, or wire colors. In Src write S for your own station kit or P for a shared item borrowed from your paired station.

#	Src	Sensor technology	Part number (exact)	Output	# wires	Evidence	Condition
1
2
3
4
5
6
7
8

Suffix pattern. Having filled the table, state the rule you deduced: in this manufacturer's part numbers, the characters _______ indicate _____________ and the characters _______ indicate _____________.

Part E Make the lamp light 16 min

Stop — destroy-the-sensor warning

Supply OFF before you land any wire. Verify 0 V at the terminal with a meter. Do not trust the switch.
The black signal wire must always reach the opposite rail through the lamp, never directly. Black straight to blue (0 V) on a PNP sensor shorts the output transistor through itself and destroys the sensor instantly, silently, and permanently. Black straight to brown (+24 V) does the same to an NPN device.
Nothing gets landed on the PLC input card this week. The sensor drives a panel lamp and nothing else.
One person lands wires, the second person reads the drawing back. Instructor checks before you energize.

Pick one three-wire discrete sensor from your kit and use a panel indicator lamp as its load. Its output type decides which rail the lamp's far leg returns to — work that out from Part B before you wire it, not by trial and error. Then demonstrate the lamp turning on when you present a target.

Sensor chosen (part number)
Its output type	PNP / NPN (circle one)
So the lamp's far leg returns to	+24 V / 0 V (circle one)
Why — one sentence, in terms of current path
Brown landed on terminal
Blue landed on terminal
Black landed on terminal
Lamp's far leg landed on terminal
Measured supply voltage before energizing
Lamp with no target present	on / off
Lamp with target present	on / off
If it did not work, what did you change?

Instructor check before energizing

Working demonstration verified

Part F Station panel — confirm what is here 6 min

Tick only what is physically present on your station panel, and write the quantity. The panels are supposed to be identical; part of your job is to find out whether they actually are. Next week's lab depends on these answers, so be accurate rather than generous.

24 VDC power supply PLC processor Discrete input card Discrete output card Analog input card Network switch VFD / variable speed drive Motor connected to VFD Indicator lamps Pushbuttons Selector switches E-stop button Terminal strips for sensors HMI / operator panel PC or laptop dock at this station

PLC make and model, exactly as printed
Input card catalog number
Ports you can see on the PLC	USB / Ethernet / serial / none (circle all)
Any label or strap marked sink, source, or common? Write it exactly

Part G Return the kit 10 min · before you leave

Nobody leaves until the kit is reconciled

De-energize the panel. Disconnect your sensor and pull your patch leads off the terminal strip.
Coil leads loosely — do not kink them or wrap them tightly around the barrel.
Count every item back against the kit list. Return shared items to the cabinet, not to your pair's bin.
If something is missing or was damaged during the session, say so now. Reporting it costs you nothing. A sensor quietly returned broken costs the next class their lab.

Returned by	Time in	All items returned?	Damage or loss to report	Instructor initials

Part H Debrief take-home · submit in Canvas before next lab

Two sensors in your kit had nearly identical part numbers but opposite output types. Write both part numbers and explain exactly which characters differ and what they mean.
You wire a PNP sensor with the lamp's far leg returned to +24 V instead of 0 V. The sensor's own LED lights when you present a target, but the lamp never does. Explain, in terms of current path, why.
Your kit contains a capacitive and an inductive proximity sensor. Name one target each would detect that the other would miss.
A line must detect a clear plastic bottle moving on a conveyor. Which device in your kit would you specify, and which one would you specifically avoid, and why?
Two sensor types had to be shared between your station and your pair because the lab does not stock six of them. If you were specifying a purchase to fix that, which two would you buy, how many of each, and what would you tell the person approving the spend?