> For the complete documentation index, see [llms.txt](https://docs.creativeconners.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.creativeconners.com/docs/machinery/smart-chain-hoist/under-the-hood.md).
# Under The Hood
Typically, you will not need to open your Smart Chain Hoist. However, you may need to adjust the limits due to installation conditions, or you may need to access the terminal blocks for advanced troubleshooting.
## OPENING THE MACHINE
On each side of the hoist, there is a hood to protect the mechanics and electrical connections inside. The limits are covered by the hood that has a label with the load rating of the machine and (4) SHCS.
These screws need to be loosened to take the limit enclosure hood off and access the inside of the Smart Chain Hoist. To open the Smart Chain Hoist, you will need a 3/16” Allen key. Be aware, each hood has a gasket which must be reseated properly.
 
Inside the limit enclosure hood, you’ll find the Smart Chain Hoist’s rotatable limit switch and position encoder, as well as its motor and load brakes.
The motor enclosure hood protects the motor, speed encoder, and most of its wiring. This hood is held in place with (2) SHCS and has a label with the CM/Lodestar logo.
Like the limit enclosure, you will need to loosen the two screws with a 3/16” Allen Key. Once taken off, you will see the motor and signal wiring, as well as the motor and speed encoder.
 
There shouldn’t be a need to open this side of the hoist, however it’s always nice to know what you’re looking at.
## SETTING THE LIMITS
Setting limits is important for operating any automated effect. Setting limits prevents the machine from moving past a safe location, protecting the machine and the load attached. The limits for the Smart Chain Hoist are inside the enclosure and are pre-set from the factory to allow the maximum chain travel while keeping the machine from damaging itself.
There may come a time when your installation requires resetting the limits for a particular installation. Keep in mind that you will also need to restore those limits at the end of the run.
The Smart Chain Hoist includes four limits:
* FWD Ultimate
* FWD
* REV
* REV Ultimate
The initial and ultimate limits are factory set the correct distance apart to not inadvertently trip an Ultimate Limit.
These limits are actuated by rotary discs on a threaded rod driven by a worm gear. The discs are indexed for a capture plate to keep them from free spinning once the limit is set. As the motor runs, the discs are pulled along the threaded rod until they make contact with the limit switch.
To adjust the position of your rotary discs, you will need to loosen the two 5/32” SHCS that keep your capture plate engaged with your discs.
 
Once the screws have been loosened and the capture plate has been disengaged from the rotary discs, you can freely spin the discs to your desired position to adjust where they will engage the limit switches.
 
Once set, place the capture plate back into position, indexing with the rotary discs, and tighten the 5/32” screws. Once you test that the limits are engaging where you want them, you can replace your limit hood onto the hoist enclosure.
## ADJUSTING THE DISTANCE BETWEEN INITIAL LIMIT AND ULTIMATE LIMIT
It is also possible to move the initial limits closer or farther away from the ultimate limits, although we don’t recommend doing so unless you're also seeing the Ultimate Limit trip at the same time as the Initial Limit.
* The two initial limit plates are locked in place by (3) PHCS.
* The middle screw locks both plates down
* Each plate has an individual screw locking it down as well.
### STEPS TO ADJUST THE INITIAL AND ULTIMATE LIMIT RELATIONSHIP
1. Loosen the center screw.
2. Loosen the second screw corresponding to the limits you would like to adjust
3. Pivot the limit on the indexing pin, moving the initial limit closer or farther away from the ultimate limit.
* Remember that the Ultimate Limit is stationing and doesn't move.
## POSITION SCALE
Each Smart Chain Hoist has its own position scale. This is a departure from most of our stock machines and is due to small variances in each hoist. The Spikemark Machine Library has a stock position scale, but to achieve the most accurate positioning you will need to set the position scale for each Smart Chain Hoist. To ease this process, each machine has the Position Scale noted on a label, directly above the electrical specs.
This number will need to be set in the Position Scale field in Spikemark. If you are having trouble with the scaling on your Smart Chain Hoist, you can calculate and adjust either by using our Position Scale Wizard or by calculating the math yourself.
 
To adjust your scaling, bring the Smart Chain Hoist’s hoisting hook down to where you want your “zero” point to be. Bring up the Position Scale Wizard, reset your zero, and run the hoisting hook to your maximum allowable height. Measure the distance from zero to this height and input that number into the position wizard and it will calculate the position scale for you. If you do not want to use the Wizard, you can calculate your position scaling with the formula shown below.
###
## BRAKE TESTING
The Stagehand Pro can control two brakes for use in hoisting applications. The Stagehand Pro will internally check the electronic systems to ensure the brake circuits are working properly before releasing either the motor brake or the load brake to prevent dropping a suspended piece of scenery. However, the Stagehand cannot confirm that the brakes are mechanically operating correctly.
Since the Stagehand cannot confirm that both brakes are functioning mechanically and that neither has jammed in a released state (very rare, but possible), the brakes should be tested at every install and nightly pre-show check. The Stagehand has convenient buttons on the faceplate to assist you with testing the brakes. To test that your brakes are operating correctly on your Smart Chain Hoist, read through the following steps in their entirety and then perform each action as follows:
* Clear the stage below the suspended scenery
* Press the Brake Test button
* While holding the Brake Test Button, press the Load Brake button. This will manually release the Load Brake. The Motor Brake should still be engaged and will hold the load. If the suspended scenery slips down, release the Load Brake button immediately. Since the Motor Brake did not hold the load as expected, that brake has failed. DO NOT OPERATE THE MACHINE UNTIL THE MOTOR BRAKE IS REPAIRED OR REPLACED. FAILURE TO REMOVE THE MACHINE FROM SERVICE COULD RESULT IN DAMAGE, INJURY, OR DEATH.
* Provided the Motor Brake passed the functional test, release the Load Brake button.
* While holding the Brake Test Button, press the Motor Brake button. This will manually release the Motor Brake. The Load Brake should still be engaged and will hold the load. If the suspended scenery slips down, release the Motor Brake button immediately. Since the Load Brake did not hold the load as expected, that brake has failed. DO NOT OPERATE THE MACHINE UNTIL THE LOAD BRAKE IS REPAIRED OR REPLACED. FAILURE TO REMOVE THE MACHINE FROM SERVICE COULD RESULT IN DAMAGE, INJURY, OR DEATH.
* Release the Motor Brake button
Pro Tip: If you press all three buttons at once, all brakes will engage
For use with the Smart Chain Hoist, we suggest that this procedure be executed every night to ensure that all equipment is operating in a safe, reliable manner.
## VFD SETTINGS
The parameter settings on the Mitsubishi Variable Frequency Drive (VFD) are tailored to make the unit work effectively with each machine. Check out our [**Stagehand Parameters**](/docs/stagehand/stagehand-parameters.md) for more information on [determining your Stagehand model](/docs/stagehand.md) and even [restoring your VFD Parameters](/docs/stagehand/stagehand-parameters/all-clear-parameter-clear.md)
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