4 Feed Axis Operation
4.6.2 Speed Control Command (VELCTRL: 3C Hex)
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4.6.2
Speed Control Command (VELCTRL: 3C Hex)
Use the VELCTRL (3C hex) command to send speed references from the host controller to the SERVOPACK.
The speed reference unit that is used by the Speed Control command is set in common parameters 41 (PnA82)
and 42 (PnA84).
The factory settings are for reference units/s to pulses/s.
Note 1. The VELCTRL (3C hex) command does not accept speed feedforward (VFF) references. Create a speed refer-
ence that includes the speed feedforward in the host controller.
2. You can select the gain (SVCMD_IO.G-SEL) with the VELCTRL (3C hex) command as well.
However, the SERVOPACK’s position loop gain (kp) does not affect motor behavior. Prepare the position loop
gain (kp) at the host controller and select the position loop gain to match the gain selection (SVCMD_IO.G-
SEL).
Field
Description
CMD
Ox3C
CMD_CTRL
−
SVCMD_CTRL
−
SVCMD_IO
−
TFF
Torque Feedforward
The torque unit is set in common parameters
47 and 48. Normally, the percent of the rated
torque is selected.
VREF
Speed Reference
The speed unit is set in common parameters
41 and 42. Normally, reference units/s is
selected.
ACCR
Acceleration Rate
When the host controller is used to perform
position control, set the maximum accelera-
tion rate (FFFF FFFF hex).
DECR
Deceleration Rate
When the host controller is used to perform
position control, set the maximum decelera-
tion rate (FFFF FFFF hex).
TLIM
Torque Limit
The torque unit is set in common parameters
47 and 48.
Normally, FFFF FFFF hex (i.e., no torque
limit) is set.
Usable Phase
2 or 3
Processing Time
Within the communi-
cations cycle
Byte
VELCTRL
Command
Response
0
3C hex
3C hex
1
WDT
RWDT
2
CMD_CTRL
CMD_STAT
3
4
SVCMD_CTRL
SVCMD_STAT
5
6
7
8
SVCMD_IO
SVCMD_IO
9
10
11
12
TFF
CPRM_SEL_
MON1
13
14
15
16
VREF
CPRM_SEL_
MON2
17
18
19
20
ACCR
MONITOR1
21
22
23
24
DECR
MONITOR2
25
26
27
28
TLIM
MONITOR3
29
30
31