Setting the Work Envelope by Mechanical Stops
Mechanical stops set the absolute work envelope that physically limits where the Manipulator can move.
Both Joints #1 and #2 have threaded holes in positions corresponding to angles for the setting area. The positions of the mechanical stops (variable) set the work envelope. Install the bolts in the threaded holes corresponding to the angles to be set.
Joint #3 can be set to any length less than the maximum stroke.
Table top mounting specifications
| Symbol | Description |
|---|---|
| a | Joint #3 mechanical stop (lower limit mechanical stop) |
| b | Joint #3 mechanical stop (upper limit mechanical stop) *Do not move the position of the upper limit mechanical stop. |
| c | Joint #2 mechanical stop (adjustable) |
| d | Joint #1 mechanical stop (adjustable) |
| e | Joint #1 mechanical stop (fixed) |
| f | Joint #2 mechanical stop (fixed) |
Multiple mounting specifications
For the model with multiple mounting specifications, only the stop positions that are different from the model with table top mounting specifications are explained here.
| Symbol | Description |
|---|---|
| a | Joint #1 mechanical stop (adjustable) |
| b | Joint #1 mechanical stop (fixed) |
Setting the Mechanical Stops of Joints #1 and #2
Both Joints #1 and #2 have threaded holes in positions corresponding to angles for the setting area. The positions of the mechanical stops (variable) set the work envelope.
Use the following procedure to install the bolts in the threaded holes corresponding to the angles to be set.
Turn off the Controller.
Install a hexagon socket head cap bolt into the threaded hole corresponding to the setting angle, and tighten it.
Joint # Hexagon Socket Head Cap Bolt Number of Bolts Recommended Tightening Torque Strength 1, 2 M8 × 10 Total thread 1 for each side 18.0 N∙m (194 kgf∙cm) ISO 898-1 property class 10.9 or 12.9 equivalent Turn on the Controller.
Set the pulse range corresponding to the new positions of the mechanical stops.
KEY POINTS
Be sure to set the pulse range inside the positions of the mechanical stop range.
Example: Setting Joint #1 to -110° to +110° and Joint #2 to -120° to +120° for the GX4-A**1S*
Execute the following command in [Command Window].>JRANGE 1,-582542,5825423 'Sets the pulse range of Joint #1 >JRANGE 2,-2184533,2184533 'Sets the pulse range of Joint #2 >RANGE 'Confirms the setting value using the Range statement -582542, 5825423,-2184533,2184533,-1706667 ,0, -1310720, 1310720Move the arm by hand until it touches the mechanical stops to check that nothing will hinder the arm motion during operation, such as by hitting peripheral equipment.
Operate the joint with the new settings at low speeds until it reaches the positions of the minimum and maximum values of the pulse range. Check that the arm does not hit any mechanical stops.
(Check the position of the mechanical stops and the motion range that were set.)
Example: Setting Joint #1 to -110° to +110° and Joint #2 to -120° to +120° for the GX4-A**1S*
Execute the following command in [Command Window].>MOTOR ON 'Turns on the motor >POWER LOW 'Sets to low power mode >SPEED 5 'Sets to low speed >PULSE -582542,0,0,0 'Moves to the minimum pulse position of Joint #1 >PULSE 5825423,0,0,0 'Moves to the maximum pulse position of Joint #1 >PULSE 2621440,-2184533,0,0 'Moves to the minimum pulse position of Joint #2 >PULSE 2621440,2184533,0,0 'Moves to the maximum pulse position of Joint #2The Pulse statement (Go Pulse statement) moves all joints to the specified positions at the same time. Set safe positions after taking into consideration the motion of the joints whose pulse range have been changed and also the other joints.
In this example, when checking Joint #2, Joint #1 is moved to the 0° position (pulse value: 2621440) near the center of its work envelope.
If the arm hits a mechanical stop or if an error occurs after the arm hits a mechanical stop, either reset the pulse range to a narrower pulse range so that nothing blocks the arm motion, or extend the positions of the mechanical stops within the limit.
Joint #1 mechanical stop
Views from the bottom of Arm #1
| Mounting Specifications | Arm Length (mm) | Arm Shape | Mechanical Stop Position | |||
|---|---|---|---|---|---|---|
| a | b | c | ||||
| Max. motion range (deg.) | Table top | 250 | Straight | ±140 | -110 | +110 |
| 300 | Straight | |||||
| 350 | Straight | |||||
| Left-curved | -165 to 110 | -150 | +95 | |||
| Right-curved | -110 to 165 | -95 | +150 | |||
| Multiple | 300 | Straight | ±115 | -102.6 | +102.6 | |
| 350 | Straight | ±120 | -103.5 | +103.5 | ||
| Max. pulse range (pulse) | Table top | 250 | Straight | -1456356 ~ 6699236 | -582542 | 5825423 |
| 300 | Straight | |||||
| 350 | Straight | |||||
| Left-curved | -2184534 to 5825423 | -1747627 | 5388516 | |||
| Right-curved | -582543 to 7427414 | -145636 | 6990507 | |||
| Multiple | 300 | Straight | -728178 to 5971058 | -367002 | 5609882 | |
| 350 | Straight | -873814 to 6116694 | -393216 | 5636096 | ||
Joint #2 mechanical stop
| Mounting Specifications | Arm Length (mm) | Arm Shape | Environmental Specifications | Mechanical Stop Position | |||
|---|---|---|---|---|---|---|---|
| a | b | c | |||||
| Max. motion range (deg.) | Table top | 250 | Straight | S, E | ±141 | -111 | +111 |
| C | ±137 | -107 | +107 | ||||
| 300 | Straight | S, E | ±142 | -112 | +112 | ||
| C | ±141 | -111 | +111 | ||||
| 350 | Straight | S, E, C | ±142 | -112 | +112 | ||
| Left-curved | S, E | -165 to 120 | -135 | +90 | |||
| C | -160 to 120 | -130 | +90 | ||||
| Right-curved | S, E | -120 to 165 | -90 | +135 | |||
| C | -120 to 160 | -90 | +130 | ||||
| Multiple | 300 | Straight | S, E, C | ±135 | -105 | +105 | |
| 350 | Straight | S, C | ±142 | -112 | +112 | ||
| Max. pulse range (pulse) | Table top | 250 | Straight | S, E | -2566827 to 2566827 | -2020693 | +2020693 |
| C | -2494009 to 2494009 | -1947876 | +1947876 | ||||
| 300 | Straight | S, E | -2585032 to 2585032 | -2038898 | +2038898 | ||
| C | -2566827 to 2566827 | -2020693 | +2020693 | ||||
| 350 | Straight | S, E, C | -2585032 to 2585032 | -2038898 | +2038898 | ||
| Left-curved | S, E | -3003734 to 2184534 | -2457600 | +1638400 | |||
| C | -2912712 to 2184534 | -2366578 | +1638400 | ||||
| Right-curved | S, E | -2184534 to 3003734 | -1638400 | +2457600 | |||
| C | -2184534 to 2912712 | -1638400 | +2366578 | ||||
| Multiple | 300 | Straight | S, E, C | -2457600 to 2457600 | -1911467 | +1911467 | |
| 350 | Straight | S, E, C | -2585032 to 2585032 | -2038898 | +2038898 | ||
KEY POINTS
For models with multiple mounting specifications, the work envelope cannot be completely limited because the Manipulator could hit a wall within the setting range of the mechanical stops.
Setting the Mechanical Stop of Joint #3
KEY POINTS
This method can be used only for the Manipulator models with standard specifications (GX4-***1S*) and ESD specifications (GX4-***1E*).
For Manipulators with cleanroom & ESD specifications (GX4-***1C*), the work envelope set by the Joint #3 mechanical stop cannot be changed.
Turn on the Controller, and turn off the motors using the Motor OFF statement.
Push up the shaft while pressing the brake release switch.
Do not push the shaft up to its upper limit or it will be difficult for the arm top cover to be removed. Push the shaft up to a position where the Joint #3 mechanical stop can be changed.
Symbol Description a Brake release switch b Lower limit mechanical stop mounting screw M3 × 10 c Shaft KEY POINTS
When you press the brake release switch, the shaft may lower due to the weight of the hand. Be sure to hold the shaft by hand while pressing the switch.
Turn off the Controller.
Loosen the lower limit mechanical stop screw (M3 × 10).
KEY POINTS
A mechanical stop is mounted on both the top and bottom of Joint #3. However, only the position of the lower limit mechanical stop on the top can be changed. Do not remove the upper limit mechanical stop on the bottom because the origin position of Joint #3 is determined by this stop.
The upper end of the shaft defines the maximum stroke position. Move the lower limit mechanical stop down by the length that you want to limit the stroke.
For example, when the lower limit mechanical stop is set at the "150 mm" stroke, the lower limit Z coordinate value is "-150". To change this value to "-130", move the lower limit mechanical stop down by 20 mm. Use calipers or similar tool to measure the distance when adjusting the mechanical stop.
Symbol Description a Measurement length Firmly tighten the lower limit mechanical stop screw (M3 × 10) while being careful that it does not enter the shaft groove.
Recommended tightening torque: 2.4 N·m (25 kgf·cm)Turn on the Controller.
Press down Joint #3 while pressing the brake release switch, and then check the lower limit position. Do not lower the mechanical stop too far. Otherwise, the joint may not reach a target position.
Calculate the lower limit pulse value of the pulse range using the formula shown below, and set the value.
The result of the calculation is always negative because the lower limit Z coordinate value is negative.
GX4-A/GX4-B/GX4-C**1S*(Z:-150 mm): Lower limit of pulse = (lower limit Z coordinate value)/16 × 131072 × (50/36)Example: To lower the mechanical stop by 50 mm and change the lower limit Z coordinate value to "-100" with a 150 mm stroke
(-100)/16131072 × (50/36) = -1137778
Execute the following command in [Command Window].>JRANGE 3,-1137778 ,0 ' Sets the pulse range of Joint #3Using the Pulse statement (Go Pulse statement), move Joint #3 to the lower limit position of the pulse range that was set at low speed.
If the mechanical stop range is less than the pulse range, Joint #3 will hit the mechanical stop and an error will occur. When an error occurs, either change the pulse range to a narrower setting or extend the position of the mechanical stop within the limit.Example: To lower the mechanical stop by 50 mm and change the lower limit Z coordinate value to "-100" with a 150 mm stroke
Execute the following command in [Command Window]. Enter the value calculated in Step (9) for -1137778.>MOTOR ON 'Turns on the motor >SPEED 5 'Sets to low speed >PULSE 0,0,-1137778,0 ' Moves to the lower limit pulse position of Joint #3(In this example, all pulses except those for Joint #3 are "0". Substitute these "0" values with the other pulse values to specify a position where interference will not occur even when lowering Joint #3.)