A Baldor Servo System was purchased to replace a custom analog servo system
used to rotator the dome of the IRTF Telescople Facility.
1. General Requirement
1.0 Motor Velocity and Acceleration
The Dome's Maximum velocity is 2 deg/sec.
The Dome's Maximum acceleration is 0.166 deg/s^2. (0 to 2 deg/s in 12 seconds).
The motor are attached to the dome via:
gear box 1:24.64 ratio
spur gear 76/21 ratio
boggie wheel 768/20 ratio.
total ratio is 1:3424.25.
Using a baldor motor shaft rotation of 4096 counts,
this table summarizes the Dome rates vs the motor rates:
Dome deg/sec Motor RPM Motor cnts/sec
------------ ------------ ---------------
Max Vel: 2.0 1141.42 77920.7
Max Accel: 0.166 6493.4
Where:
RMP_motor_shaft = dome_deg/s * (1/360 R/deg * 60/1 sec/min) = RPM_dome * 3424.25 gearing.
= dome_deg/s * 570.708333
IRTF will attemp to resurface it's dome rails. To do this it is necessay to
move the dome at 10 inches per minute. This would translate to 0.025 deg per
second of dome rotation. Motor units: RPM is 14.26 RPM, or 974 cnt/sec.
1.1 Interface with facility Telescope Control System (TCS)
A Telescope Control System (TCS) in the facility determines when it is necessary
to move the dome. It produces a velocity request for the Dome Servo System.
We desired to commnicate this velocity/mode command using ethernet. And to
query status data (faults, mode, temperature, vel, currents, etc) using ethernet.
It is desire to perform this command/query at 10Hz (but 5Hz could be acceptable).
The IRTF has implemented a subset of function from "MN1949, Mint API access via TCP/IP"
to allow the TCS to Set/Get COMMs variables from the e100. The master e100's COMM array
should be used to exchange this information.
A IRTF safety circuit will provide TTL Enable/Disable output to disable the amplifers
independent of any other controls, software, etc. The servo system must disable any
movement on this signal.
A typical move sequece would be:
set jog mode (by writing to COMM variable, release brakes)
wait 2 second
ramp up velocity to desired speed (TCS write to COMMS velocity variable at 5/10Hz)
ramp down velocity to zero
wait 2 second
goto idle mode (by writing to COMM variable, enable brakes).
2. Baldor Hardware and Software Configuration
2.1 Servo System Hardware
3 each MFE460A021B Motiflex E100B 21Amp controller.
OPT-MF-013 Baldor Resolver w/ simulator encoder.
1 each OPT-MF-101 Baldor Mint AultAxis Motiflex card
Install in 1 of the E100B controllers
1 each OPT036-501 Baldor Ethernet Power Routers.
3 each BSM100C-3150BA, Baldor Servo Motors
2.2 Ethernet Configuration
The e100 will be attached using it's EPL network.
The Power Router will allow connection to the IRTF LAB.
The e100 with Mint Card is the Manager node (NodeID 0xFE)
The other e100 are node 0x64, 0x65.
Attached Router, E100 using EPL, and Router to IRTF LAN.
Here is the router IP values for the Hilo and Summit Network:
hostname HILO IP NUMBER SUMMIT IP Number EPL Network IP NodeID
----------- --------------- --------------- -------------- ---------
t3epl 128.171.110.226 128.171.165.137 192.168.100.254 0xFE (default)
t3e100-1 128.171.110.227 128.171.165.138 192.168.100.240 0xF0 (240, manager node)
t3e100-2 128.171.110.228 128.171.165.139 192.168.100.100 0x64 (100, control node)
t3e100-3 128.171.110.229 128.171.165.140 192.168.100.101 0x65 (101, control node)
2.3 E100 configuration
Set up the axis as in the E100 node 0xf0
axis 0 - internal Axis
axis 1 - remote axis node 0x64
axis 2 - remote axis node 0x65
The other 2 E100 would try to match the velocity off the master's e100 axis.
Mint Application would monitor COMM array for brake and velocity requests.
Set/Disable brake on command.
Set Axis 0 in motion, per velocity command.
Axis 1, 2 to match velocity of Axis 0.
[ Need to figure is out]
2.3 E100 COMM Array and MINT Application
The Mint Application show the COMM array layout.