Interfacing The Proportional Current Driver - Curtis 1239E Manual

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INTERFACING THE PROPORTIONAL CURRENT DRIVER

Note: The 1239E and 1269E applications typically do not utilize the proportional current drivers as
used in material handling trucks. See the 1232E-1238E manual (53096) for the parameters. Contact
Curtis to enable these parameters, which will require a different OS parameter block.
VCL code can directly interface the proportional current driver (PD), as shown in Figure 20. VCL
Quick Link:
Figure 20
p.116
can change the working parameters of the PD and can provide the command.
NOTE: Proportional Drivers are not typically used with the 1239E/1269E controller. If the application
calls for proportional drivers, contact the Curtis distributor or the Curtis sales-support office for
technical assistance.
Depending on how the PD system is to be used, certain parameters need to be set; they can be set
via the 1313/1314 handheld programmer or via VCL.
1. PD_Enable must be set On for current control, otherwise the PD_Output will be controlled
2. Hyd_Lower_Enable must be set On to use the throttle input to control lowering in a
3. Hyd_Lower_Enable must be set Off to allow using a VCL variable (VCL_PD_Throttle) as
Once the PD parameters are set, the PD_Throttle variable will be mapped between PD_Min_Current
and PD_Max_Current and sent to the dither function. Note that Mapped_Throttle is inverted;
lowering its value (making it more negative) increases the PD_Throttle value.
The Dither function adds and subtracts from the current command to the PD based on PD_ Dither_Percent,
at a rate set by PD_Dither_Period. The dithered current command is compared to the present PD_Current
and the error is fed into a PI controller. The feedback gains are set by the parameters PD Kp (proportional
gain) and PD Ki (integral gain).
The output of the PI controller becomes the driver's pulse width modulation, thus controlling the
average current of the driver. The final output is the VCL variable PD_Output, which is displayed in
the 1313/1314 Monitor » Inputs menu as PD PWM.
The following PD processing variables are accessible by VCL:
CAN Object Index
10 — VEHICLE CONTROL LANGUAGE (VCL)
by the VCL function Put_PWM(PWM5,xxxx), which is voltage control.
hydraulic lift/lower system.
the PD command.
VCL Variable
Access
Mapped_Throttle
Read Only
0x3211 0x00
VCL_PD_Throttle
Read/Write
0x320E 0x00
PD_Throttle
Read Only
0x3210 0x00
PD_Current
Read Only
0x321C 0x00
PD_Output
Read Only
0x321E 0x00
Curtis 1239E-1269E Manual, os 37.0 RevA – May 2021
Description
Command from throttle section.
VCL-accessible PD command.
Resultant command to the PD.
Average current flowing in the PD.
Resultant PWM at PD output.
pg. 115