AMS DCB-274 User Manual
ADVANCED MICRO SYSTEMS, INC.
SMC-27X2 SOFTWARE
3 6
Function
Type
NV Bytes
Set Jog Speeds
Default, Immediate, Program
3
Command
B
Mnemonic
(Name) B (n1, n2)
(Name) B (n1, n2)
Data 1
Slow Speed (0-255)
Slow Speed (0-255)
Data 2
High Speed (0-255)
High Speed (0-255)
Result
None
None
B (Set Jog Speeds)
These two numbers represent the speeds to use for jog inputs. The first is usually a lowe r speed. The
second number is used when the high-speed jog (pin J1-9) is held low. The values are multiplied by 30 to
determine the actual step rate in FULL steps per second. The controller automatically scales the step rates to
maintain a constant shaft RPM when the microstep resolution is changed.
Setting values of 0 will disable the jog. Speeds are divided by the “D” value. The power-up settings are
stored in NV memory.
This command is generally implemented during the initial customer default parameter assignment. However,
it may be implemented and changed within a program. Following, is an example:
second number is used when the high-speed jog (pin J1-9) is held low. The values are multiplied by 30 to
determine the actual step rate in FULL steps per second. The controller automatically scales the step rates to
maintain a constant shaft RPM when the microstep resolution is changed.
Setting values of 0 will disable the jog. Speeds are divided by the “D” value. The power-up settings are
stored in NV memory.
This command is generally implemented during the initial customer default parameter assignment. However,
it may be implemented and changed within a program. Following, is an example:
P 0
Enters program mode.
B 0 0
Disable jog switches.
+ 100000
Move 100000 in the plus direction.
W 0
Wait until move is complete.
B 30 100
Re-enable jog switches.
P
Exit program mode.
Function
Type
NV Bytes
Set Slow or Fast Decay
Default, Immediate, Program
2
Command
b
Mnemonic
(Name) b (0, 255)
(Name) b (0, 255)
Data 1
Speed Threshold
Speed Threshold
Data 2
Result
None
None
b (lower case B; Fast and Slow Decay)
The DCB-274 has been designed to add both Slow and Fast decay. When there is no motion (stopped), the
decay will always be slow. The threshold defines a motor speed where slow decay changes to fast decay
during acceleration and switches back to slow decay during decele ration. The threshold will occur at an
RPM where step resolution is taken into account.
decay will always be slow. The threshold defines a motor speed where slow decay changes to fast decay
during acceleration and switches back to slow decay during decele ration. The threshold will occur at an
RPM where step resolution is taken into account.
Threshold
Value
Value
½ SPS
1/8 SPS
0
Fast
Fast
25
650
2400
50
1300
4800
100
2400
9600
150
3700
14000
200
5000
19200
255
Slow
Because the step rate is actually measured, the decay detection functions for external step pulse input. Slow
decay provides smooth operation with reduced resonance’s at slow to medium speeds. Fast decay will
generally enhance high-speed operation at speeds above 200-300 RPM. The actual settings usually must be
determined empirically (see Addendum: “About Step Motor Current”) and tailored to the specific design.