Servo Amp Module Upgrade Notice to 8XX Series This document provides information and differences on upgrading previous series of Servo Amplifier Modules to the -8XX series module. - Oilgear - #1

1. ' Set the balance switches to the hexadecimal pre­liminary numbers 7F. This is the mid-point, or zero set­ting of the amplifier 256 divided by 2 = 128 (7F) mid point of +/-range.

2. If the system balance requires adjustment, increasing the numbers from 7F equates to rotating the old style balance potentiometer clockwise (more positive), and decreasing the number equates to rotating the old style balance potentiometer counterclockwise (more negative).

3. The placement of the balance range jumpers and pump stroke determine physical stroke increment obtained. For each coarse or fine switch increment there is, therefore a corresponding pump or control move­ment (neutral response).

4. All feedback positions on pump volume commands will use this balance setting as the minimum, home or neutral position for referencing amplifier commands.

5. Some applications require critical, precise balance adjustments. Many applications utilize hydraulic valves to bypass flows or pressures resulting from slight off sets from precise non-balance settings.

6. One-way pump applications may utilize the balance adjustments to keep the pump from crossing to the non-delivery side or to insure the pump is held slightly against the minimum or neutral volume stop. Typically against the stop LVDT voltages are in the range of 0.05 to 0.25 VDC while running.

7. Since balance adjustments determine the starting point for stroke or volume commands, the balance may affect final full stroke or volume positions attainable.

The SERVO AMPLIFIER MODULE L404563-000 thru 799, manufactured by The Oilgear Company has been discontinued and replaced with SERVO AMPLIFIER MODULE, part number L404563-8XX series. This pub­lication explains the user differences.

The balance and main gain adjustments of the SERVO AMPLIFIER MODULE, part number L404563-8XX series are made via two (2) pairs of hexadecimal rotary switches, which are accessed through the front of the module cover. The left switch of each pair is the most significant digit, or coarse adjustment; the right switch is the least significant digit, or fine adjustment.

The switches are hexadecimal, meaning they have 16 positions each. The positions increase in value from "0" to "F", as the switches are rotated clockwise. When the right switch (least significant digit) roll over from "F' to "0" clockwise, the left switch (most significant digit) must be incremented one clockwise increment. When the right switch (least significant digit) rolls over from "0" to "F" counterclockwise, the left switch (most significant didgit) must be incremented one counter­clockwise increment. This provides 256 different com­binations of settings.