Elmo SSA Series Brushed DC Servo Amplifiers

Elmo SSA-6/100 on eBay

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.

Pages 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)