User`s guide

300 SERIES USER GUIDE
28
IR-Comp
Setup Procedure
Two methods are presented here. Use the one that seems to be the most appropriate to
your installation, and equipment available.
First, remember that IR-comp is used in the voltage mode. So determine that the voltage
gain of the amplifier has been set correctly (see proceeding section).
Next set the trimpots as follows:
Feedback pot (R42) = Max CW ; Minimum loop gain
Voltage Feedback pot (R31) = Max CCW ; Lowest voltage gain
IR Comp pot (R51) = Max CCW ; Zero IR comp
Current Limit pot (R41) = Max CW ; Maximum current
Balance pot (R61) = Centered ; Minimum offset
Finally, be sure that the p.c. board jumpers are set correctly:
Jumper Pins
JP 62 2-3
JP 63 2-3
JP 64 1-2
Table 19
Static Setup Method
Equipment required: Voltmeter, DC source (A 1.5V battery and a switch will do)
1. Adjust the Feedback pot CCW until oscillation appears (squealing sound). Turn pot 2 turns
CW. Oscillation should cease.
2. Find motor armature resistance from datasheet. Add to this the motor brush resistance to find
total resistance seen by amplifier.
3. Adjust Reference voltage for a test current that is about 20% of full value. Check current
monitor to confirm this current. I.e., the current monitor shows 6.0V at amplifier peak current.
Adjust
Vref
for a monitor output of 1 volt.
4. Compute the test current as follows:
I
VI
V
arm
mon peak
=
×
6
Fig. 15
I
arm
= Motor armature current
V
monitor
= Current monitor voltage
I
peak
= Amplifier peak current rating
5. Lock the motor shaft to prevent rotation, and with the test current flowing through the load,
adjust the IR Comp pot (R51) such that the output voltage increases by an amount Vdiff:
Vdiff = I
arm
X R
arm
( Output voltage increase )
I
arm
= Armature current
R
arm
= Armature resistance
6. Monitor the motor for overheating while performing this procedure. Apply the test voltage in an
on-adjust-off fashion. Note that the motor must be stationary while making this adjustment.