2-Button E-Stop

RMP 210, 220, 440LE, 440SE, 440 Omni
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sdnalloh
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Joined: Tue Aug 07, 2012 1:27 pm
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2-Button E-Stop

Post by sdnalloh » Mon Jun 15, 2015 11:43 am

E-Stop Photo 2.jpg
Intuitive Interface
  • Push either E-Stop button and the RMP slows to a stop (DTZ).
  • Push the other button (both buttons pressed) and the RMP turns off (Disable).
  • Buttons can be in one box (above) or in two separate boxes.
Background
The 09-18-14 firmware release changed how the RMP responds to Decel-To-Zero (DTZ) commands. Previously, the RMP would decelerate to zero velocity, then immediately power off. Now, the RMP decelerates to zero velocity and remains on, holding position. This is advantageous for balancing platforms because it means the RMP will continue to Balance, instead of powering off and falling over. This is also advantageous for non-balancing platforms because it means the RMP will not roll downhill if it has stopped on a slope.

It is almost always better to issue a DTZ command rather than a Disable command in an emergency. The DTZ command will cause the RMP to come to a stop and hold position, whereas the Disable command will power off the RMP immediately. If the RMP is travelling fast, cutting power (Disable) will not slow the RMP; instead, it will continue to roll until stopped by an external force (i.e. until it crashes).

However, there are still situations where a Disable command is desirable. For example, a non-user may need to power off the RMP, but may not know where the power switch is. The E-Stop button provides a universally-recognized way to cut power to a device. Similarly, some jurisdictions may require the use of an E-Stop that cuts power to the RMP.


Wiring
To make your own, use E-Stop buttons with two switches: one Normally-Open, and one Normally-Closed.
Use a 6-pin MIL-DTL-38999/24FB98PN connector to interface with the RMP's User Interface Box.
E-Stop-03.png
  • Disable (pin C) must be pulled up to 5V for the RMP to function normally (connect pins A and C). Open the circuit to send a Disable command.
  • DTZ (pin B) must be open for the RMP to function normally. Pull it up to 5V (connect pins A and B) to send a DTZ command.
  • BOOT 1 (pin E) can be pulled down to ground (connect pins D and E) to enter Diagnostic Mode (during startup) or to send a Balance Mode request (from Standby Mode or Tractor Mode).
  • Boot 2 (pin F) can be pulled down to ground (connect pins D and F) to enter Bootloader Mode (during startup).

Code: Select all

E-Stop 1           E-Stop 2            DTZ               Disable
--------           --------            -----             -------
   Up                 Up               Open                5V
   Up                Down               5V                 5V
  Down                Up                5V                 5V
  Down               Down               5V                Open
NOTE
  • The DTZ circuit must be Open for the RMP to function normally. Closing the DTZ circuit will cause the RMP to Decel-To-Zero.
  • The Disable circuit must be Closed for the RMP to remain on. Opening the Disable circuit will cause the RMP to power off.
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