BG Series

Goniometric Cradles

±45° transverse axis rotation with maximum free access to the rotating platform (±30° for BGS50)
Nested cradles provide orthogonal rotation about the same point
Precision machined ball bearing races assure smooth motion and high stability
Precision ground worm gear provides 0.001° resolution
Vacuum compatible versions up to 10^-6 hPa

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Overview
Specifications
Ordering
Drawings
Literature & Downloads
Controller
Related Products

BG Series goniometric cradles rotate on a transverse axis above the platform. Compared to full 360° rotation stages, they offer maximum free access to the rotating part and allow construction of very compact multi-axis rotation assemblies. BG cradles are designed so that orthogonal mounting of two adjacent-size cradles (e.g., BGS50 and BGS80) provides two perpendicular rotational axes intersecting at about the same point in space. Mounting a rotation stage under the assembly adds a third orthogonal rotation axis through the same point.

Precision rotation is ensured by a precision ground, hardened worm gear drive. Single row ball bearings and precision ground tool-steel races ensure smooth rotation with minimal wobble and eccentricity. A home switch, conveniently located at the center of travel, facilitates the return of the platform to a level position.

BG Series goniometric cradles are available in 5 sizes and may be configured with DC motors or stepper motors. The selection of the motorization is dependent on the application.

Motor Drive Versions

Stepper-motor-driven goniometers are available in a mini-step (PP) and full step (PE) versions. The PP mini-step drive version enables high angular speeds up to 20°/sec. The larger models BGM120PP to BGM200PP feature a worm mounted rotary encoder for improved accuracy and repeatability. The encoder also provides a method for detecting motor stalling, an important feature for applications with high loads or torques.

The BGS50PP and BGS80PP are not equipped with an encoder and position is attained by the number of commanded steps or micro-steps. The high output torque of the stepper motor, combined with extensive performance tests, ensures position accuracy as long as the recommended load and torque are not exceeded. The BGS50PP and BGS80PP provide very high motion sensitivity with good linearity between commanded micro-steps and the actual motion of the stage.

The PE full-step version with a reduction gear provides a higher torque and is recommended for high inertia payloads and vacuum applications. This version is available only on the BGM120 to BGM200 size.

The DC-motor driven versions use three different motors and encoders depending on the size of the cradle. The BGS50CC uses a miniature DC servo motor with a motor mounted rotary encoder, a reduction gear and a belt drive in order to fold the motor. The result is a very small and lightweight package providing a very high resolution output and great minimum incremental motion capability. However, reversibility is compromised due to some backlash and hysteresis in the reduction gear and belt drive system.

The BGS80CC features a high resolution 4,000 cts/rev rotary encoder with index pulse for precision homing and is the recommended choice for applications requiring accurate bi-directional positioning. For tightest position control, the rotary encoder is directly mounted on the worm screw. This avoids the majority of drive train error sources that affect other stages with indirect position read out. The BGM120CC to BGM200CC use high torque DC motors. This motor also features a built-in tachometer to provide superior speed stability.

For the definition of specifications see Motion Basics and Standards.

Motor cables are included.

Design Details

Base Material	Stainless steel with aluminum body
Bearings	Ball bearings
Drive Mechanism	Ground worm gear
Worm Gear Ratio	BGS50, BGS80 and BGM120: 1:180 BGM160 and BGM200: 1:60
Reduction Gear	BGS50CC: 14:1, BGS50PP: 43:1 BGS80CC: 44:20 BGS80PP and BGM120¹⁾: None BGM160¹⁾ and BGM200¹⁾: 3:1
Feedback	BGS50CC: Motor mounted rotary encoder, 2048 cts/rev BGS50PP and BGS80PP: none BGS80CC: Worm mounted rotary encoder with index pulse, 4000 cts/rev BGM120 to BGM200: Worm mounted rotary encoder with index pulse, 2000 cts/rev
Limit Switches	Mechanical, at ± 45° (for BGS50 Mechanical, at ± 30°)
Origin	Optical, at 0°
Cable	3 m long cable included. Sub-D25 connector. Sub-D15 for BGS80.
Vacuum Compatibility	Available up to 10^-6 Torr using full step motor (BGM120PE to BGM200PE only)

¹⁾ Additional motor mounted 10:1 reduction gear on PE versions.

Specifications

	BGS50CC	BGS50PP	BGS80CC	BGS80PP	BGM120, BGM160 BGM200
Travel Range (°)	±30	±30	±45	±45	±45
Resolution (°)	0.0000698	0.00001938⁽¹⁾	0.0005	0.0001⁽²⁾	0.001
Minimum Incremental Motion (°)	0.0005	0.0002	0.0005	0.0002	0.002
Uni-directional Repeatability Typical¹ (°)	0.001	0.001	0.001	0.001	0.004
Reversal Value (Hysteresis), Guaranteed, Typical⁽³⁾ (°)	0.012	0.015	0.002	0.004	0.02
Bi-directional Repeatability, Typical¹ (°)	0.013 or ± 0.0065	0.016 or ± 0.008	0.003 or ± 0.0015	0.005 or ± 0.0025	0.024 or ± 0.012
Absolute Accuracy, Typical¹ (°)	0.05 ° or ± 0.025	0.07 or ± 0.035	0.05 ° or ± 0.025	0.06 ° or ± 0.03	0.05 ° or ± 0.025
Maximum Speed (°/s)	10	4	20	20	CC and PP: 20 PE: 2
Wobble, Typical¹ (µrad)	200 or ± 100	200 or ± 100	200 or ± 100	200 or ± 100	200 or ± 100
MTBF (h)	20,000
Weight [lb (kg)]	1.76 (0.8)	1.76 (0.8)	4.6 (2.1)	4.6 (2.1)	BGM120: 18.7 (8.5) BGM160: 39.7 (18) BGM200: 83.8 (38)

¹ Shown are peak to peak, typical specifications or ± half the value as sometimes shown. For the definition of typical specifications which are about 2X better than the guaranteed values, see Motion Control Metrology Primer. The actual performance of BG stages are not verified on all production units, hence typical specifications are provided.

Load Characteristics and Stiffness

		BGS50	BGS80	BGM120	BGM160	BGM200
Cz, Normal centered load capacity (N)		20	60	200	300	500
a, Construction parameter (mm)		30	40	70	90	120
kα, Radial compliance (µrad/Nm)		100	20	10	5	2
My, Maximum torque (Nm)	(PE)			10	20	29
	(PP)	0.5	1	6	16	17
	(CC)	0.5	1	9	10	10
Q, Off-center load: Q ≤ Cz/(1 + D/a), where D = Cantilever distance in mm

Model	Description	avail raw	Availability	price raw	Price	Qty. MULTI ADD
BGM120CC	BGM120 Goniometer, ±45° Travel Range, 0.001° Resolution, DC motor drive	4	4 Weeks	9125	$9,125.00	ADD
BGM120PE	BGM120 Goniometer, ±45° Travel Range, 0.001° Resolution, Full-step drive	4	4 Weeks	9605	$9,605.00	ADD
BGM120PEV6	BGM120 Goniometer, ±45° Travel Range, 0.001° Resolution, Full-step, Vacuum	7	7 Weeks	15415	$15,415.00	ADD
BGM120PP	BGM120 Goniometer, ±45° Travel Range, 0.001° Resolution, Micro-step drive	4	4 Weeks	9030	$9,030.00	ADD
BGM160CC	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, DC motor drive	4	4 Weeks	14595	$14,595.00	ADD
BGM160PE	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Full-step drive	6	6 Weeks	14975	$14,975.00	ADD
BGM160PEV6	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Full-step, Vacuum	7	7 Weeks	17660	$17,660.00	ADD
BGM160PP	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Micro-step drive	6	6 Weeks	13905	$13,905.00	ADD
BGM200CC	BGM200 Goniometer, ±45 ° Travel Range, 0.001° Resolution, DC motor drive	6	6 Weeks	18800	$18,800.00	ADD
BGM200PE	BGM200 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Full-step drive	6	6 Weeks	19185	$19,185.00	ADD
BGM200PEV6	BGM200 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Full-step, Vacuum	8	8 Weeks	24215	$24,215.00	ADD
BGM200PP	BGM200 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Micro-step drive	6	6 Weeks	18680	$18,680.00	ADD
BGS50-BP	Base plate for BGS50	3	3 Weeks	125	$125.00	ADD
BGS50CC	BGS50 Goniometer, ±30 ° Travel Range, 0.001° Resolution, DC motor drive	0	In Stock	4190	$4,190.00	ADD
BGS50PP	BGS50 Goniometer, ±30 ° Travel Range, 0.001° Resolution, Micro-step drive	0	In Stock	3955	$3,955.00	ADD
BGS80CC	BGS80 Goniometer, ±45 ° Travel Range, 0.001° Resolution, DC motor drive	0	In Stock	5300	$5,300.00	ADD
BGS80PP	BGS80 Goniometer, ±45 ° Travel Range, 0.0001° Resolution, Micro-step drive	0	In Stock	4945	$4,945.00	ADD
M-BGM120CC	BGM120 Goniometer, ±45° Travel Range, 0.001° Resolution, DC motor, Metric	4	4 Weeks	9125	$9,125.00	ADD
M-BGM120PE	BGM120 Goniometer, ±45° Travel Range, 0.001° Resolution, Full-step, Metric	4	4 Weeks	9605	$9,605.00	ADD
M-BGM120PEV6	BGM120 Goniometer, ±45° Travel, 0.001° Resolution, Full-step, Vacuum, Metric	6	6 Weeks	15415	$15,415.00	ADD
M-BGM120PP	BGM120 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Micro-step, Metric	4	4 Weeks	9030	$9,030.00	ADD
M-BGM160CC	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, DC motor, Metric	6	6 Weeks	14595	$14,595.00	ADD
M-BGM160PE	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Full-step, Metric	6	6 Weeks	14975	$14,975.00	ADD
M-BGM160PEV6	BGM160 Goniometer, ±45 ° Travel, 0.001° Resolution, Full-step, Vacuum, Metric	6	6 Weeks	17660	$17,660.00	ADD
M-BGM160PP	BGM160 Goniometer, ±45 ° Travel Range, 0.001° Resolution, Micro-step, Metric	6	6 Weeks	13905	$13,905.00	ADD
M-BGM200CC	BGM200 Goniometer, ±45° Travel Range, 0.001° Resolution, DC motor, Metric	6	6 Weeks	18800	$18,800.00	ADD
M-BGM200PE	BGM200 Goniometer, ±45° Travel Range, 0.001° Resolution, Full-step, Metric	6	6 Weeks	19185	$19,185.00	ADD
M-BGM200PEV6	BGM200 Goniometer, ±45° Travel, 0.001° Resolution, Full-step, Vacuum, Metric	8	8 Weeks	24215	$24,215.00	ADD
M-BGM200PP	BGM200 Goniometer, ±45° Travel Range, 0.001° Resolution, Micro-step, Metric	6	6 Weeks	18680	$18,680.00	ADD

	Thread	Spacing
Model	B	C	Z (No. Holes)
BGM120CC (M-BGM120CC)	1/4-20 (M6)	25.4 (25)	15
BGM160CC (M-BGM160CC)	1/4-20 (M6)	25.4 (25)	21
BGM200CC (M-BGM200CC)	1/4-20 (M6)	25.4 (25)	49

	Diameter	Dimension (mm)
Model	D	E	F	G	H	J	K	M	N	P	Q	R	S	T	U	V	W
BGM120CC (M-BGM120CC)	6.8	152.4 x 50.8	150 x 100	120	120	170	206	31	70	94	164	180	8	99	128	6	43.2
BGM160CC (M-BGM160CC)	6.8	203.2 x 101.6	200 x 150	170	160	220	350	8.7	99	138.2	245	270	10	130	197.5	10	46.8
BGM200CC (M-BGM200CC)	6.8	254 x 203.2	250 x 250	270	200	270	520		135	196	360	398	10	200	300	10	62.5

Application Notes

MotionAppNote-LaserGatedImaging (322 KB)

Data Sheets

BG Data Sheet (1 MB)

Newport Resource e-Catalogs *

*e-Catalog pages include the most current information available at the time of printing.

Technical References

RoHS Compliance Certificate (139 KB)

User Manuals

BG User Manual (1 MB)
BGM User Manual (2 MB)

Controller Compatibility

Family	Max. Power Consumption (W)	XPS¹ driver module	Compatibility
Family	Max. Power Consumption (W)	XPS¹ driver module	ESP301¹	SMC100CC¹	SMC100PP¹
BGM120CC to BGM200CC	60	XPS-DRV01	x
BGM120PE to BGM200PE	20	XPS-DRV01	X		X
BGM120PP to BGM200PP	60	XPS-DRV01	X
BGS50CC⁴	10	XPS-DRV01	X	X
BGS80CC	40	XPS-DRV01	X	X
BGS50PP	10	XPS-DRV01	X		X
BGS80PP	20	XPS-DRV01	X		Reduced^2,3

1. Enhanced System Performance (ESP) Controller
2. Compatible, but speed is reduced by 2.5x of the rated speed (ie, 40% of rated speed).
3. Compatible, but MIM is 1/20th of a full step.

XPS Series

Model	Description
XPS-C2	2-axis Universal Controller/Driver, ethernet
XPS-C4	4-axis Universal Controller/Driver, ethernet
XPS-C6	6-axis Universal Controller/Driver, ethernet
XPS-C8	8-axis Universal Controller/Driver, ethernet
XPS-DRV01	PWM drive module for DC brush and stepper motors, 3A/48V max.

ESP301 Series

Model	Description
ESP301-1G	ESP301 Motor Controller/Driver, 1 axis, w/ GPIB and USB
ESP301-1N	ESP301 Motor Controller/Driver, 1 axis, USB
ESP301-2G	ESP301 Motor Controller/Driver, 2 axis, w/ GPIB and USB
ESP301-2N	ESP301 Motor Controller/Driver, 2 axis, USB
ESP301-3G	ESP301 Motor Controller/Driver, 3 axis, w/ GPIB and USB
ESP301-3N	ESP301 Motor Controller/Driver, 3 axis, USB

SMC Series

Model	Description
SMC100CC	Single-axis DC motor controller/driver
SMC100PP	Single-axis stepper motor controller/driver

Note: Refer to SMC series product page for power supply and available cable accessories

	Description
	Motorized Rotation Stage Selection Guide
	Stage and Controller Compatibility