Power, Torque & Speed

Encoder Resolution Calculator

State what the encoder datasheet number counts, then calculate channel cycles and decoded events separately. The result is a numerical rate/increment check, not an accuracy or electrical compatibility specification.

Enter exactly what the datasheet counts. Linear travel is optional; angular increments remain available.

CALCULATION SETUP

Inputs

Do not assume PPR/CPR has a universal meaning. Check the actual manufacturer definition.

If input is already decoded, divide by this factor to recover an integer channel-cycle count; no second x4 multiplication.

Ratio 2 means two encoder revolutions for one load revolution.

RPM

Leave blank if linear motion is not known; no linear increment is inferred.

Optional except in Maximum RPM mode; use the actual counter's counting convention.

Calculated locally in your browser. No sign-up or input upload.

CALCULATED VALUE

Results

Linear increment per decoded count

0.00125 mm0.000049213 in

Load angular increment per decoded count

0.09 deg0.001571 rad

Encoder angular increment per decoded count

0.09 deg0.001571 rad

Channel cycles per encoder revolution

1,000

Decoded counts per encoder revolution

4,000

Decoded counts per load revolution

4,000

Channel-cycle rate

100,000 Hz100 kHz

Decoded count-event rate

400,000 counts/s400 kcounts/s

Encoder shaft speed

6,000 RPM

Load shaft speed

6,000 RPM

Maximum encoder RPM under entered criterion

3,000 RPM

Maximum load RPM under entered criterion

3,000 RPM
Channel cycle versus decoded eventsA and B square waves are offset by one quarter cycle. x1 marks one A edge, x2 marks both A edges, x4 marks four A/B transitions. This schematic does not establish electrical timing or direction wiring.ABOne channel cyclex4: 4 defined count events per channel cycle
Channel cycles and decoded events have different meanings. 1,000 cycles × x4 = 4,000 decoded counts per encoder revolution. Waveform is schematic; accuracy and electrical compatibility remain separate.

Calculation breakdown

Entered resolution means
Channel cycles per encoder revolution, before the selected decoding factor.
Count normalization
1,000 channel cycles/rev × x4 = 4,000 decoded counts/rev.
Shaft ratio
Encoder revolutions / load revolution. Encoder and load RPM are reported separately.
Entered rate criterion
Decoded count events per second, after the chosen quadrature factor.

Only the result summary and canonical link are shared. Inputs and free-form names are excluded.

Assumptions & checks

Resolution is not accuracy or repeatability. CPR/PPR naming differs between manufacturers; check the datasheet definition.

Numerical rate compliance does not establish electrical compatibility, input filtering, wiring, mechanical speed or signal integrity. Incremental A/B only; absolute/index/protocol support is outside this model.

Entered shaft speed exceeds your rate criterion on the selected channel/decoded basis.

Verify inputs & continue

Channel-cycle/decoded-count conventions and the entered rate basis are explicit. Arithmetic resolution requirements do not establish product availability or accuracy.

US Digital manufacturer cycle/count convention

Use data for the actual component and operating conditions. Continue with the related calculations below after reviewing the selected result.

Formula

Explicit incremental A/B channel-cycle and quadrature-decoded conventions

Cdecoded = Cchannel × k (k=1,2,4). fchannel = Cchannel × nencoder / 60; fdecoded = Cdecoded × nencoder / 60. i = encoder rev/load rev. Counts/load rev = Cdecoded × i; linear increment = L/(Cdecoded × i). nmax = 60 × limit/(cycles or decoded counts per rev, matching the limit basis). Reverse channel requirement = ceil(required decoded counts/k).

Worked example

Using the default values shown in the calculator, the same formula gives the following result. This is a quick sanity check for the calculation, not a design recommendation.

Inputs

Entered resolution convention
Channel cycles per encoder revolution
Datasheet resolution value
1000
Quadrature decoding factor
x4
Encoder revolutions / load revolution
1
RPM refers to
Encoder shaft
Shaft speed
6000 RPM
Linear travel per load revolution
5 mm
Rate-limit basis
Decoded count events per second
Decoded count-event rate limit
200000 counts/s

Result

Linear increment per decoded count
0.00125 mm
Load angular increment per decoded count
0.09 deg
Encoder angular increment per decoded count
0.09 deg
Channel cycles per encoder revolution
1,000
Decoded counts per encoder revolution
4,000
Decoded counts per load revolution
4,000
Channel-cycle rate
100,000 Hz
Decoded count-event rate
400,000 counts/s
Encoder shaft speed
6,000 RPM
Load shaft speed
6,000 RPM
Maximum encoder RPM under entered criterion
3,000 RPM
Maximum load RPM under entered criterion
3,000 RPM

REAL INPUTS · CLEAR METHOD

Practical worked examples

Illustrative scenarios using this page’s calculation or verified reference model. Change the assumptions for your own job.

Already decoded 4000 counts, x4

Given

Entered resolution convention
Already decoded counts per encoder revolution
Datasheet resolution value
4000
Quadrature decoding factor
x4
Encoder revolutions / load revolution
1
RPM refers to
Encoder shaft
Shaft speed
6000 RPM
Linear travel per load revolution
5 mm
Rate-limit basis
Decoded count events per second
Decoded count-event rate limit
200000 counts/s
Calculation / lookup method

Cdecoded = Cchannel × k (k=1,2,4). fchannel = Cchannel × nencoder / 60; fdecoded = Cdecoded × nencoder / 60. i = encoder rev/load rev. Counts/load rev = Cdecoded × i; linear increment = L/(Cdecoded × i). nmax = 60 × limit/(cycles or decoded counts per rev, matching the limit basis). Reverse channel requirement = ceil(required decoded counts/k).

Result

Channel-cycle rate
100,000 Hz
Linear increment per decoded count
0.00125 mm
Load angular increment per decoded count
0.09 deg
Encoder angular increment per decoded count
0.09 deg
Channel cycles per encoder revolution
1,000
Decoded counts per encoder revolution
4,000

4000 already decoded counts correspond to 1000 underlying channel cycles. The result is 100 kHz channel and 400000 counts/s, not a second x4 multiplication.

1001 decoded counts required with x4

Given

Quadrature decoding factor
x4
Encoder revolutions / load revolution
1
Linear travel per load revolution
5 mm
Target load increment
Linear increment
Target linear increment
0.004995004995004995 mm
Actual selected channel cycles/rev (optional)
251
Calculation / lookup method

Cdecoded = Cchannel × k (k=1,2,4). fchannel = Cchannel × nencoder / 60; fdecoded = Cdecoded × nencoder / 60. i = encoder rev/load rev. Counts/load rev = Cdecoded × i; linear increment = L/(Cdecoded × i). nmax = 60 × limit/(cycles or decoded counts per rev, matching the limit basis). Reverse channel requirement = ceil(required decoded counts/k).

Result

Minimum integer channel cycles/rev
251
Mathematical decoded-count requirement
1,001
Coherent decoded-count requirement
1,004
Increment at calculated cycle requirement
0.00498008 mm
Actual entered decoded counts/rev
1,004
Actual entered linear increment
0.00498008 mm

1001/4 rounds upward to 251 underlying cycles, producing 1004 coherent decoded counts. This arithmetic does not establish that an encoder is stocked or suitable.

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Frequently asked questions

Can I use a PPR or CPR number directly?

Only after reading what it counts. Enter channel cycles or already decoded counts explicitly; names are not universal conventions.

What happens with an already decoded x4 value?

The tool divides it by four to recover channel cycles and checks that the result is an integer. It does not multiply an already decoded value by four again.

Why are channel and count rates different?

x4 decoding counts four defined quadrature events per channel cycle. A channel-cycle frequency specification and decoded counter-event limit use different denominators.

Does count increment mean accuracy?

No. Accuracy, repeatability, filtering, mechanics and signal quality are distinct specifications.

How is reverse resolution rounded?

First calculate the decoded-count requirement. Divide by the decoding factor, ceil the underlying integer cycles, and multiply back. 1001 required counts at x4 becomes 251 channel cycles and 1004 decoded counts; no hardware availability is inferred.

Reference data & method sources

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