§3 xArm 850
Major Components
The parts of the system, what each one does, and how they connect.
Start Here
This section names the parts of the system, says what each one does, and shows how they connect. Every tier below starts from the same three facts.
12
pins on the tool connector1
48 V
power the control box sends to the arm2
AC or DC
control box: mains, or 48–72 V DC for mobile platforms3
- The system is more than the arm: an arm, a control box, cables, and a tool on the end that does the work45.
- The control box houses the arm's control system6.
- The emergency stop button is on the control box, not on the arm7.
S2 in one line: S2 is the xArm 850 arm that picks up incoming material and moves it between receiving, staging and production89.
Look Back
A question from earlier on, to keep it fresh. Skip it if you like; nothing depends on it.
Choose your depth
1Beginner
The Parts You Can See
For: Anyone with no robotics background: a visitor, a new operator, a manager
Kind of task: Recognize and recall, with plain-language explanations and pictures
In this part you open the box, name each part, and find the one button everyone near the arm must be able to reach. No robotics background is needed.
What Comes in the Box
- The package holds the arm, a control box, a power and signal cable that joins the arm to the box, a power cable for the box, an adapter cable for the tool, and Ethernet cables4.
- A control box is included by default: the arm is always sold as part of a system10.
The Arm
- The arm has a base and six rotary joints, numbered Joint 1 at the base to Joint 6. Joint 6 is the tool end, where tools attach11.
- It is built from carbon fiber and aluminum, which UFACTORY says halves the weight of the system12.
The Control Box
The control box is the core of the system: it houses the arm's control system6.

- Its front panel has three lights. ROBOT PWR shows the arm has power, STATE shows the controller has power, and LAN shows communication7.
- The same panel carries the EMERGENCY STOP button7.
- That is why UFACTORY says the control box must sit outside the arm's working range, where the button can be reached in an emergency13.
The Tool on the End
- The end effector is the tool on the front of the wrist, such as a gripper or a vacuum gripper. It is the part that touches the workpiece and does the work5.
- UFACTORY's own options for the 850 are a Gripper, a Vacuum Gripper, the BIO Gripper G2 and a force-torque sensor14.
- At S2, the arm's attachment is a single suction aperture15.
Brakes in the Joints
The joints contain brakes. If the power is lost, they hold the arm where it is instead of letting it fall16.
The Software
Check Yourself
Answer, then check. Each option has its own feedback, and nothing is scored.
2Novice
How the Parts Work Together
For: Someone who will work near or with the cell: operator, trainee technician
Kind of task: Explain and sequence: put steps in order, match parts to their functions
In this part you follow a command from a computer all the way to the gripper, and learn the handful of rules that protect the arm and the people beside it. It is for someone who will work near or with the cell.
From a Click to a Moving Gripper
This platform pieces together the path a command takes from UFACTORY's separate descriptions of each part. The UFACTORY sources do not describe the whole path in one place, so the path is Inferred, and its reasoning is printed with the record25.
- A computer sends the command over Ethernet to the control box25.
- The control box runs UFACTORY Studio and the controller, which work out what the arm must do25.
- Through the power and signal cable, the box powers the arm at 48 V DC and talks to the joints over an RS-485 line252.
- A second RS-485 line in the same cable carries the tool's traffic252.
- The gripper at the flange gets 24 V power and its control signals through the 12-pin tool connector251.
Two Kinds of Control Box
UFACTORY offers two boxes. The AC box has a built-in AC-DC adapter, for mains power. The DC box takes 48–72 V DC, for battery-powered mobile platforms3.

What Studio Holds, and What Is Missing
- Studio includes Live Control, Blockly graphical programming, a Python IDE and GCode26.
- No dedicated teach pendant is documented for the 850. People teach it in UFACTORY Studio, or by guiding it by hand27.
- In manual mode, gravity compensation lets you guide the arm by hand. How easily it gives is set by a teach sensitivity from level 1 to 528.
- Collision sensitivity is set from 0, which turns collision detection off, up to 529.
Fitting a Tool
- A UFACTORY Gripper or Vacuum Gripper is fixed to the end of the arm with 2 M6 bolts and connected with its connection cable with the arm powered off, the e-stop pressed and the arm's power light off. UFACTORY says this avoids arm failure caused by hot-plugging30.
- The Vacuum Gripper handles smooth, flat objects up to 5 kg. It has 5 suction cups. It is switched on and off by digital I/O31.
- In Studio's End Effector setting you choose the 850 Gripper, Vacuum Gripper or BIO Gripper, or a Robotiq 2F-85 or 2F-140. Any other tool is set as "other"32.
The Tool at S2
- S2 uses a single suction aperture as its attachment15.
- S2's and S6's suction tools are basically the same attachment: a rounded mount with the cups attached as one unit. S6's tool uses all five ports on the mount; S2's uses just one33.
When the Sources Disagree About the Gripper
Check Yourself
Answer, then check. Each option has its own feedback, and nothing is scored.
3Intermediate
Installing and Connecting the Parts
For: Someone who will set up, program or maintain the arm: technician, student engineer
Kind of task: Apply: work through written scenarios that need a decision (which mode, which setting, what to do about this error), with feedback on each choice
In this part you work through what installing the system involves: power, cables, the tool flange, the network line inside the arm, and the rules for storage and the brakes. It is for someone who will set up, program or maintain the arm.
Power into the Control Box
- The AC control box takes mains power through a standard IEC C20 inlet, with an IEC C19 cable37.
- Inside, a switching power supply turns 100–240 V AC into 12 V and 48 V DC, which power the box itself and the arm38.
- UFACTORY says to place the control box between 0.6 m and 1.5 m above the floor39.
Cables
- The cable from the arm to the control box has an 8-pin industrial connector. It carries 48 V and ground, plus two RS-485 buses: one for the arm and one for the tool2.
- Use only the original arm cable, and do not use the arm where that cable has to bend. Longer or flexible cables are available through the supplier40.
- I/O cables from the control box to other equipment must not be longer than 30 m, unless testing shows a longer run works41.
- With the DC control box, the arm connects through a supplied Robot Pwr & Communication Adapter Cable42.
The Tool Flange and Connector
- The tool flange follows the standard ISO 9409-1-50-4-M643.
- It has six M6 threaded holes and one Ø6 positioning hole, and takes end effectors of two different sizes44.
- Power and control signals reach grippers and sensors through a 12-pin female aviation-style socket at the tool side1.
A Network Line Inside the Arm
- An Ethernet cable runs inside the arm, from a user RJ45 port on the base to an M8 4-pole connector at the end flange. A camera or other device at the tool can reach the network through it45.
- Its speed is disputed. The product page and online manual say gigabit, 1000M CAT5E; the older User Manual says 100M, standard CAT546.
- This project's advice: until someone checks the arm at S2, size any device at the tool, such as a camera, for 100M, the lower figure47.
The Battery, and the Brakes
- The arm has a built-in battery. If it is stored unused for 3 months or more, UFACTORY says to power it on for 6 hours every 3 months to charge it36.
- Studio can release the joint brakes ("unlock joint"). When it does, someone must hold the arm up, or it will fall48.
What the Emergency Stop Does

- The e-stop button on the control box performs a Stop Category 149.
- When it is pressed, the arm brakes slightly and falls. UFACTORY says the e-stop should not be used as a risk-reduction measure50.
- The manual's own e-stop descriptions do not fit together: one part says arm power is removed quickly, while another calls the stop Category 1, which decelerates with drive power on. The contradiction card sets out both sides51.
Gripper Figures You Will Be Asked For
- The online manual rates the Gripper G2 (AG1200) for a 5 kg payload52. It weighs 800 g53.
- Its clamping force is 10–50 N54, its stroke 84 ± 1 mm55, and its speed 15–225 mm/s56.
- It talks RS-485 with Modbus RTU, runs on 24 V DC, has replaceable fingers and is rated IP4057. Its cycle life is more than 2,000,000 cycles58.
- The Vacuum Gripper (AS1200) weighs 610 g and measures 122.5 × 91.6 × 75 mm59.
- The product page and the 850 manuals give no specification for the BIO Gripper G2 or the force-torque sensor: only their names are listed60.
- This project's advice: the gripper figures disagree between manuals, so where a UFACTORY gripper is fitted, check which one before you use any of them34.
- S2's own attachment is a suction tool rather than the Gripper G2: a single suction aperture15.
Check Yourself
Answer, then check. Each option has its own feedback, and nothing is scored.
4Expert
Electrical and Kinematic Detail
For: Someone who designs, integrates or changes the cell: integrator, engineer, agent developer
Kind of task: Analyze and decide: weigh trade-offs, resolve contradictions, critique a configuration
In this part you read the arm's geometry, its model numbers and the electrical detail of its inputs, outputs and tool pins, and learn where the detail in the UFACTORY sources runs out. It is for someone who designs, integrates or changes the cell.
The Arm's Geometry
In UFACTORY's modified D-H parameters, five link lengths describe the arm, and the uf850 kinematics file agrees with each one6364656667.
- d1, from the base up to the Joint 2 axis: 364 mm63.
- a2, the upper arm from Joint 2 to Joint 3: 390 mm64.
- a3, the offset from Joint 3 to the forearm: 150 mm65.
- d4, the forearm along Joint 4: 426 mm66.
- d6, from the Joint 5 axis to the tool flange: 90 mm67.
Model Numbers
- UFACTORY's manual gives the arm the model number XF8500 and the AC control box AC15. The online manual calls the DC controller DC850068.
- The SGS safety verification linked from the 850 manual uses other model numbers: it covers "UFACTORY Robotic Arm", XI13 and XI1569.
Inside a Joint
The joints use harmonic drives, also called strain-wave reducers, and servomotors with 17-bit encoders70.

Motor model and rating, gear ratio, encoder type and joint-module sizes for each joint are not in the manuals or the URDF71.
The Controller's Inputs and Outputs
- The control box has dedicated safety inputs: an emergency stop input and a protective stop input, each wired as a pair in two separate branches72.
- The configurable inputs CI0–CI7 can be set for Stop Moving, Safeguard Reset and Reduced Mode. The general inputs DI0–DI7 cannot73.
- The digital outputs are NPN open-collector or open-drain74.
- The internal 24 V I/O supply delivers up to 1.8 A. An external 24 V supply of up to 3 A can be connected instead75.
- Analog inputs and outputs work at 0–10 V with 12-bit resolution76.
The Tool Connector, Pin by Pin
- Pins 1–2 carry +24 V, pins 3–4 are 0 V, pins 5–6 are RS-485 A and B, pins 7–8 are tool outputs TO0 and TO1, pins 9–10 are tool inputs TI0 and TI1, and pins 11–12 are analog inputs AI0 and AI161.
- The supply is 24 V (20–30 V) at up to 1800 mA77.
- Tool outputs are NPN open-collector, sinking up to 100 mA, with no current protection78.
- Tool inputs have pull-down resistors, so an input left floating reads low. They accept up to 30 V and read high above 1.6 V79.
- Tool analog inputs are not differential, accept -0.5 to 3.3 V in voltage mode, and have 12-bit resolution80.
- Third-party RS-485 devices can be driven through the tool port. UFACTORY's own tool uses ID 9; standard Modbus RTU devices are set up under the Studio page that the 850 manual calls Settings-Externals-Modbus RTU, a section the Studio manual, as read on 2026-10-13, heads RS-485; other devices use transparent transmission8182.
- A pogo-pin connector at the tool end has the same electrical specifications as the tool I/O83.
Where the Vacuum Gripper Figures Split
The online manual's Vacuum Gripper (AS1200) gives -55 kPa, more than 4 L/min, 20 mA quiescent and 500 mA peak. The older User Manual gives 78% vacuum, more than 5.6 L/min, 30 mA quiescent and 400 mA peak. They may be different revisions; the sources do not say84.
Check Yourself
Answer, then check. Each option has its own feedback, and nothing is scored.
Not settledOpen Questions · 10
What the sources do not settle for this section. Nothing here is papered over with a plausible number.
- Kind: Gap
No dedicated teach pendant for the 850 is documented in the sources fetched: teaching is by browser (UFACTORY Studio) and by hand guiding. User Manual V2.3.0 lists stop categories for a 'Three-Position Enabling Device', but no source fetched names the product or says whether it is offered for the 850.
See reference 27 - Kind: Contradiction
Gripper specifications differ between sources: the online hardware manual's 'Gripper G2(AG1200)' has 10–50 N clamping force, 800 g weight and Modbus RTU, while User Manual V2.3.0's '850 Gripper' has 30 N maximum clamping force, 802 g weight and Modbus TCP. They may describe different gripper generations; the sources do not say.
See reference 34 - Kind: Contradiction
Sources disagree on the speed of the 850's internal base-to-flange Ethernet cable: gigabit or 1000M CAT5E on the product page and in the online hardware manual, but 100M and 'Standard CAT5' in User Manual V2.3.0.
See reference 46 - Kind: Contradiction
The 850 manual's e-stop figures appear inconsistent. Section 2.1.2 says arm power is removed within 300 ms of pressing the e-stop. Section 7.8 says the e-stop is Stop Category 1, which decelerates 'with drive power on'. Section 7.9 gives Stop Category 1 stopping times of 521 to 885 ms. The UFACTORY sources do not explain how power removal within 300 ms fits a powered deceleration lasting up to 885 ms (the brakes may do the rest of the stopping, but no source says so).
See reference 51 - Kind: Gap
No specification for the 850's BIO Gripper G2 or 6-axis force/torque sensor (payload, force range, resolution) was found in the product page or the 850 manuals fetched; only their names are listed.
See reference 60 - Kind: Gap
Per-joint component data for the 850 (motor model and rating, harmonic-drive ratio, encoder type and whether it is single- or multi-turn absolute, and joint-module sizes for J1–J6) is not published in the product page, the manuals or the URDF fetched.
See reference 71 - Kind: Contradiction
UFACTORY's documents give one page of UFACTORY Studio two names. The 850 hardware manual says a standard Modbus RTU end effector is debugged under 'Settings-Externals-Modbus RTU'. The Studio manual's Settings chapter, as read on 2026-10-13, heads its section 7.2.5, under 7.2 Externals, 'RS-485'; until that date the section was headed 'Modbus RTU'. UFACTORY's release note for Studio V2.8.2 names the page 'Settings - Externals - RS-485'; no fetched source says from which Studio version the page carries that name.
See reference 82 - Kind: Contradiction
Vacuum gripper specifications differ between sources: the online hardware manual (AS1200) gives -55 kPa, more than 4 L/min, 20 mA quiescent and 500 mA peak current, while User Manual V2.3.0 gives 78% vacuum, more than 5.6 L/min, 30 mA quiescent and 400 mA peak. They may be different product revisions; the sources do not say.
See reference 84 - Kind: Gap
The make, model and weight of S2's suction tool are not documented. It is a rounded mount with five ports, of which it uses one, basically the same attachment as S6's (int-069); that it is UFACTORY's Vacuum Gripper (AS1200), which also has five suction cups (comp-069), is not confirmed. Nor is it known whether the four unused ports are sealed.
See reference 93 - Kind: Gap
What the xArm 850's payload setting of 0.61 kg (int-552) stands for is not stated. The figure equals the weight UFACTORY lists for its Vacuum Gripper (AS1200), 610 g (comp-070), and the payload of UFACTORY Studio's preset named 'Vacuum Gripper', 0.61 kg (ops-092). The figures match; the match does not show which tool the arm carries (int-034).
See reference 94
ProvenanceReferences · 94
Each number in the text points here. Every entry states its confidence class in words and keeps its evidence one click away. How to read the labels.
Key to the badges
- Confidence: Verified
- A manufacturer or IntelliMake document says so, the project owner stated it as the design, or it was observed directly. It does not mean anyone measured it at S2.
- Confidence: Inferred
- Reasoned from Verified facts. The reasoning is printed with the record.
- Confidence: Assumed
- Plausible but untested. The record says how it would be checked.
- Kind: Gap
- Not known. No figure or answer is given in its place.
- Kind: Contradiction
- Sources disagree. Both sides are shown, and the site does not pick one silently.
- Kind: Recommendation
- Project advice drawn from the records it cites. Not a fact about the machine and not a confidence class, so the filter never hides it.
- Awaiting cell access
- Awaiting cell access: could be confirmed or corrected once the physical S2 cell can be observed.
- This project's simulation and agent design, not the physical cell
- This project's simulation and agent design, not the physical cell.
Image Credits
- Line drawings of the 850 control box with its front and back panels labeled: emergency stop, robot power, state, power switch, AC port, network port, LAN, robot 48V, enabling switch and IO. © UFACTORY (Shenzhen UFACTORY Co., Ltd.). Source. Used with UFACTORY's written permission (2026-09-23), on the condition that each image links back to its source page.
- UFACTORY's AC control box, marked 100 to 240 V AC, beside the DC control box, marked 48 to 72 V DC. © UFACTORY (Shenzhen UFACTORY Co., Ltd.). Source. Used with UFACTORY's written permission (2026-09-23), on the condition that each image links back to its source page.
- A line drawing of the 850 control box from the front, with the red emergency stop button on top and the network port, LAN, robot 48V, enabling switch, state and robot power labeled. © UFACTORY (Shenzhen UFACTORY Co., Ltd.). Source. Used with UFACTORY's written permission (2026-09-23), on the condition that each image links back to its source page.
- A cut-away render of a UFACTORY joint module showing a carbon fiber tube and a harmonic drive, with the words carbon fiber and harmonic. © UFACTORY (Shenzhen UFACTORY Co., Ltd.). Source. Used with UFACTORY's written permission (2026-09-23), on the condition that each image links back to its source page.
- 3D model: © 2018 UFACTORY Inc., BSD-3-Clause, from UFACTORY Inc. (xArm-Developer/xarm_ros2). License text · Source
Sources for This Section
- CODE_SESSION 01 — xArm 850 Interactive Learning Platform (project specification) · Derek Stringfellow (project owner)
- IntelliMake Phase 1 Factory: Autonomous Production Demonstrator (infographic) · IntelliMake.org (IntelliMake)
- Owner statements from 2026-09-24 onward (verbatim; S40 and later) · Derek Stringfellow (project owner)
- SGS Verification of MD Compliance No. MD GZES2403005468MD (UFACTORY Robotic Arm, Model No. XI13, XI15) · SGS-CSTC Standards Technical Services Co., Ltd. (published by UFACTORY) (manufacturer)
- UFACTORY 850 Hardware Manual (online), 1. Safety · UFACTORY (manufacturer)
- UFACTORY 850 Hardware Manual (online), 2. Hardware Installation · UFACTORY (manufacturer)
- UFACTORY 850 Hardware Manual (online), 3. Controller Electrical Interface · UFACTORY (manufacturer)
- UFACTORY 850 Hardware Manual (online), 4. Robotic Electrical Interface · UFACTORY (manufacturer)
- UFACTORY 850 Hardware Manual (online), 7. Production Information · UFACTORY (manufacturer)
- UFACTORY 850 Hardware Manual (online), 8. Technical Specifications · UFACTORY (manufacturer)
- UFACTORY 850 product page · UFACTORY (manufacturer)
- UFACTORY 850 User Manual V2.3.0 (PDF, older edition) · UFACTORY (manufacturer)
- UFACTORY Release Note v2.8.2 · UFACTORY (manufacturer)
- UFACTORY Studio product and download page · UFACTORY (manufacturer)
- UFACTORY Studio User Manual (online), 2. Glossary · UFACTORY (manufacturer)
- UFACTORY Studio User Manual (online), 4. Live Control · UFACTORY (manufacturer)
- UFACTORY Studio User Manual (online), 7. Settings · UFACTORY (manufacturer)
- UFACTORY Studio User Manual, 7. Settings, as it read until 2026-10-13 (publisher's repository, commit 533b75d) · UFACTORY (manufacturer)
- UFACTORY Studio's Device Info page for the xArm 850, screenshot (2026-10-16) · Derek Stringfellow (project owner)
- UFACTORY USA 850 product page · UFACTORY USA (manufacturer)
- xarm_ros2 (branch humble), xarm_description/config/kinematics/default/uf850_default_kinematics.yaml · UFACTORY (manufacturer)
IntelliMake diagrams are redrawn as native figures, © IntelliMake.org. UFACTORY does not endorse this platform.