PIPEMODE

PIPEMODE

The softMC controller can be used as a pure Motion-Bus interface card between your application and drives (PIPEMODE feature). The host computer controls all of what normally occurs in the motion module of the softMC . It must send a real-time stream of data through the softMC to the drives. In this case, the softMC functions as a data pipe. The feature is enhanced by the option of flexibly switching between pipe mode and regular mode. In typical applications, the softMC starts in regular mode where homing, jogging and initial position adjustments are made. After that, the softMC can be switched to pipe mode and the host computer takes control. There can be both softMC -controlled and pipe-controlled axes at same time in the system. Following error and velocity over-speed errors are not checked with piped axes, but by the host.

An external profiler path can be designed and fed to the softMC point-by-point. The controller functions only as a pipe and is not responsible for the correctness of the applied profiler. No system limits are checked except for position error and feedback velocity limitation. While running under this mode, no other movements are allowed.

Command points are written through the standard Fast-Data DPRAM interface and transmitted into the controller. The DPRAM is scanned every SERCOS cycle and the command is executed.

There can be up to eight (8) axes in the system operating in pipe-mode. The Fast-Data interface can be configured in one of two communication protocols using SYS.PIPEMODE: 1 – sending position command only, 2 – sending both position and velocity commands. When the system's pipe mode uses only position commands, the controller computes the current velocity. Depending on the pipe mode configuration, the controller limits the number of axes that can be operated in this mode. When system uses only position command, eight (8) axes can operate. When using both position and velocity values, only four (4) axes can operate.

Data Structure

The host CPU passes position and velocity commands via a data structure through the Fast-Data DPRAM. The API maps the data to SYS.HOSTDOUBLE. The Motion-Bus operation mode of every drive connected to an axis working in Pipe Mode must be configured (Position/Velocity/Torque). The drive operation mode is selected through a status word written in SYS.VIN.

	NOTE
	Only drive modes previously configured in the SERCOS setup can be selected.

The data structure mapping depends on the PIPEMODE state:

MC variables	Byte offset	SYSTEM.PIPEMODE
		Position (1)	Position and Velocity (2)
Sys.HostDouble[1]	0…7	A1.PCMD	A1.PCMD
Sys.HostDouble[2]	8…15	A2.PCMD	A1.VCMD
Sys.HostDouble[3]	16…23	A3.PCMD	A2.PCMD
Sys.HostDouble[4]	24…31	A4.PCMD	A2.VCMD
Sys.HostDouble[5]	32…39	A5.PCMD	A3.PCMD
Sys.HostDouble[6]	40…47	A6.PCMD	A3.VCMD
Sys.HostDouble[7]	48…55	A7.PCMD	A4.PCMD
Sys.HostDouble[8]	56…63	A8.PCMD	A4.VCMD
Sys.Vin	96…99	A1…A8 operation mode info.	A1…A4 operation mode information

Drive Operation Modes

The drive’s operation mode of every axis is set in a 2-bit field, where there are two active modes: 0 - position and 1- velocity (set in a 24-bit field SYS.VIN variable). Mapping of the SYS.VIN operation mode status variable is described below:

Bits offset	SYSTEM.PIPEMODE
	Position (1)	Position and Velocity (2)
0, 1	Operation mode of drive1	Operation mode of drive1
2, 3	Operation mode of drive2	Operation mode of drive2
4, 5	Operation mode of drive3	Operation mode of drive3
6, 7	Operation mode of drive4	Operation mode of drive4
8, 9	Operation mode of drive5	NA
10, 11	Operation mode of drive6	NA
12, 13	Operation mode of drive7	NA
14, 15	Operation mode of drive8	NA

Every sample, the controller sends the operation mode to the drive. Without any dependency at the drive’s operation mode, the controller sends the position and velocity commands to the drive.

Program
Sys.EN = Off
Sys.PIPEMODE = 2
' Definition As Position & Velocity mode
Sys.EN = On
Sys.Vin.1 = 1
' Velocity Operation Mode 
attach A1
A1.PIPEMODE =1
' Pipe mode Activation
A1.en=1
While Sys.Din.1 = 1
' External condition for Pipe Mode
sleep 1000
end while
A1.PIPEMODE = 0
' Exit from the Pipe mode 
Sys.Vin.1 = 0
' Return to the Position Operation Mode
detach A1
End Program