Elmo SSA Series Brushed DC Servo Amplifiers
Overview
Brushed DC servo amplifiers, supports current mode or tachometer feedback for velocity mode. The settings are set using resistors and capacitors across SIP sockets, though sometimes they are soldered to a monolithic PCB that is mated to the sockets instead.
Model Numbers
Page 7 in the "MAN_SSA_UG_EN_0698.pdf" (SSA Series manual) describes the model number scheme ("type designation").
Wiring Diagram
In the "MAN_SSA_UG_EN_0698.pdf" (SSA Series manual):
Page 14 shows the block diagram of the amplifier, showing where the external resistors/capacitors are being inserted into the circuitry.
Page 15 shows the physical layout of the user configurable resistors/capacitors, the potentiometers, and the connectors.
Page 16-17 describe the connector pinouts. More detailed information is in subsequent pages.
Resistor/Capacitor Settings
Default values shown for an SSA-8/100:
| Name | Value | Usage |
|---|---|---|
| C3 | [DNP] | (used for velocity mode, removed in current mode) |
| C11 | 10nF X7R | (used in current loop, set to standard value) |
| C12 | 10nF X7R | (used for velocity mode, not sure about current mode) |
| C41 | 10nF X7R | (used for velocity mode, not sure about current mode) |
| R40 | [DNP] | continuous current limit (set to rated max when not present) |
| R11 | [DNP] | (used for velocity mode, removed in current mode) |
| R6 | 33.2kΩ 1% | differential input current gain (set at 1.6) |
| R7 | 33.2kΩ 1% | differential input current gain (set at 1.6) |
| R12 | 475kΩ 1% | secondary feedback path gain (irrelevant if C3 not present) |
| R1 | [DNP] | single ended input current gain (set at 5.28) |
| R42 | 41.2kΩ 1% | peak current limit (set at 80% of rated) |
| R20 | 100kΩ 1% | (used in current loop, set to standard value) |
| R61 | [DNP] | (used for velocity mode IxR compensation, not used in current mode) |
Online Resources
SSA Series Installation & Operating Manual Rev 6/98 (direct PDF on Wayback Mach
SSA Series Installation & Operating Manual Rev 6/98 (Wayback Machine page with PDF frame)
SSA SERIES Installation & Operating Manual Rev 6/98 (original source -- remove/relocated)
SBA Series Installation & Operating Manual Rev 8/06
SBA Series Installation & Operating Manual Rev 8/06 (Wayback Machine page with PDF frame)
SBA Series Installation & Operating Manual Rev 8/06 (original source -- remove/relocated)