MX21 INSTA-MOUNT™ Series—Modular
Incremental Rotary Optical Encoder
BEI Sensors
By the time you have read this first sentence, you could have installed
BEI’s model MX21 INSTA-MOUNT™ modular optical encoder. In
addition to its quick and easy installation, the MX21 is designed to
operate with jitter-free output signals without tight controls on shaft
endplay, runout, or perpendicularity. The new INSTA-MOUNT™
encoder is capable of operating within a temperature range of -10°to
+70°C, requiring less than 30 milliamps of L.E.D. current, without
degradation of output signals and is short circuit protected.
The MX21 is perfectly suited for motor manufacturers and other high
volume OEMs. BEI’s INSTA-MOUNT™ Series encoder offers 5V TTL
compatible quadrature outputs with index and complements as options.
Axial shaft movements during operation, o f±0.010", will not adversely
affect the output signals. Shaft runouts of 0.005" TIR can also be
absorbed by this device without affecting output signal performance.
Mechanical Specifications
Dimensions:
See Figure 1
Weight:
2.1 oz. (Approx.)
Moment of Inertia:
2.6 x 10
-5
oz in sec
2
Bore Size:
see “Ordering Options”
Motor Interface
Mount Holes:
#4-40 or M3 x 0.5 @ 180° on
1.812” dia. B.C.
Mount Hardware:
2 sockethead cap screws
Perpendicularity Shaft to Mount\:
0.002” TIR
Shaft Runout:
0.005” max (each 0.0001
degrades accuracy by 0.5 arc minutes)
Shaft Endplay Dynamic or Static:
±0.010”
Shaft Finish:
16 micro inches or better. End
must be chamfered or rounded
Shaft Tolerance:
nominal -0.0002”/-0.0007”
Shaft Length:
0.56” minimum remove (remove
cover button for motor through-shafts)
Electrical Specifications
Code:
Incremental
Pulses per revolutions (PPR):
See “Ordering
Options”)
Index Pulse Options
ungated index (U)
(no index on MX212)
gated index (G)
Supply Voltage:
5 volts ±5% @ 80mA max.
Output Format:
dual channel quadrature & index
(MX212 & 213)
(no index on MX212)
(MX216)
dual channel quad & index w/ comps
Output Type:
(MX212 &213):
square wave TTL. 16mA sink
500ΩA source. Short circuit protected
(MX216):
TTL differential line driver (26LS31 or
equiv.) should be terminated into a line receiver
(26LS32, or equivalent circuit)
Frequency Response:
see graph: Fig 3
Rise Time:
1.0µ sec. max.
Environmental Specifications
Temperature:
Operating: -10°C to +70°C
Storage: -40°C to +125°C
Termination Specifications
Ribbon:
28 AWG flat ribbon cable with 10 position
connector Berg P/N 65863-165 or equiv. Mates with
Berg P/N65863-165 or equiv) (mating connector not
provided)
Round Cable:
28AWG 8 Conductor shielded cable
*NOTE:
See pinout tables, back page.
MX21 Series Encoder Ordering Options:
for assistance, call 800.350.2727
Use this diagram, working from left to right to construct your model number (example:
MX213-38-512-G-R18)
MX21
OUTPUT FORMAT:
2= Quadrature
3= Quadrature w / index
6= Quadrature w / index &
complements
X
XX
BORE SIZE:
25 = .25”
38 = .375”
6M = 6mm
8M = 8mm,
10M = 10mm
XXXX
X
INDEX OPTION
*For Output Formats 3
and 6 ONLY
G= gated to data A & B
U= ungated
XXX
ELECTRICAL TERMINATION:
Cxx = Round Shielded Cable
Rxx = Ribbon Cable with 10 Pin Socket
Header
(xx = length of cable in inches; 18 inches
standard)
PULSES PER REVOLUTION (PPR):
200, 400, 500, 512, 1000, 1024
Tel: 805-968-0782 /800-350-2727 | Fax: 805-968-3154 /800-960-2726 | 7230 Hollister Ave., Goleta, CA 93117-2807 |
www.beiied.com
Specification No. 02122-001 Rev11-10
MX21 INSTA-MOUNT™ Series—Modular
Incremental Rotary Optical Encoder
Dimensions
BEI Sensors
Output
Waveform
360°E NOM
180°E NOM
90°E NOM
A
A
B
Installation
Instructions
B
INDEX GATED TO A&B
90°E TO 450°E
INDEX UNGATED
INDEX
INDEX
CCW ROTATION OF SHAFT
MX212 outputs A & B ONLY
MX213 outputs A, B & INDEX ONLY
MX216 outputs as shown
Figure 3
Preparation:
1. Inspect motor interface per MX21 Data Sheet or specification drawing.
2. Motor shaft must be free of burrs & other surface defects.
Installation:
1. Motor shaft should NOT be rotating during initial encoder installation.
2. Hold encoder perpendicular to motor shaft. Guide the encoder onto the motor shaft,
pushing encoder STRAIGHT on until it is flush against the mount surface. Do NOT
rock side to side.
3. Install two #4-40 mount screws. Do not fully tighten at this point. (Note: A thread
sealant should be applied to the screw threads)
4. Rotate the motor shaft (300 RPM, minimum). Press the air-gap button until it
bottoms to the top of the encoder momentarily, then release. CAUTION: DO NOT
press air-gap button while motor shaft is stationary. Button should only be pressed
for one or two seconds while shaft is rotating.
5. Tighten mounting screws fully. (recommended torque is 30 to 40 ounce inches.)
6. This completes the mechanical installation. Proceed with electrical connections as
indicated on product data sheet or specification drawing.
Removal:
1. Motor shaft may be stationary or rotating up to 1000 RPM during encoder removal.
2. Remove two mounting screws.
3. Grasp encoder firmly and pull STRAIGHT off of the motor shaft. Do NOT rock side
to side.
Terminations
These commodities, technology or software if exported from the United States must be in accordance with the Bureau of
Industry, and Security, Export Administration regulations. Diversion contrary to U.S law is prohibited.
Tel: 805-968-0782 /800-350-2727 | Fax: 805-968-3154 /800-960-2726 | 7230 Hollister Ave., Goleta, CA 93117-2807 |
www.beiied.com
Specification No. 02122-001 Rev11-10