Application Note 1427
Opto-Isolation Option for the ICM-1900/ICM-2900
Overview:
The ICM/AMP-1900 and ICM-2900 modules from Galil have an option for optoisolated outputs. This option is specified by including the name -OPTO when
ordering.
FROM
CONTROLLER
ICM-1900 / ICM-2900
CONNECTIONS
ISO OUT POWER (ICM-1900,PIN 19)
OUT POWER (ICM-2900)
+5V
RP3
10K OHMS
RP4 on ICM-1900
RP2 on ICM-2900
LOAD (OPTO-MODULE, ETC)
OUT[x] (66 - 73)
OUT[x] TTL
ISO POWER GND (ICM-1900,PIN 35)
OUT GND (ICM-2900)
The ISO OUT POWER (OUT POWER ON ICM-2900) and ISO POWER GND
(OUT GND ON ICM-2900) signals should be connected to an isolated power supply.
This power supply should be used only to power the outputs in order to obtain
isolation from the controller. The signal "OUT[x]" is one of the isolated digital
outputs where X stands for the digital output terminals.
The default configuration is for active high outputs. When the controller is
configured in this manner, the opto-isolated outputs will sink current when the
outputs are set low and will not sink current when the outputs are high. To invert the
sense of the outputs, see the discussion below, “Inverting the Logic Sense of the
Opto-Isolation”
NOTE: If power is applied to the outputs with an isolated power supply but power is
not applied to the controller, the outputs will float high (unable to sink current). This
may present a problem when using active high logic and care should be taken. Using
active low logic should avoid any problems associated with the outputs floating high.
The opto-isolation provides 25mA drive current / output with approximately 400 usec
response time.
-1Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com
Inverting the Logic Sense of the Opto-Isolation:
It is often useful to invert the logic sense of the Galil outputs. Commonly used optoisolation modules such as those by OPTO-22 or Grayhill operate with negative true
logic. With this type of module, it is desirable to drive these modules with an open
collector output. Furthermore, it is important for the default and power-on state of
these outputs to be non-active. Using the opto-isolation option, this can be easily
provided by inverting the output. If the logic sense has been inverted, when the
outputs are set low (using the command CB) the opto-isolation output will be inactive. When the outputs are set high (using the command SB), the opto-isolation
output will be active (sink current).
To invert the opto-isolation outputs, remove the resistor pack on RP3, turn the resistor
pack around 180 degrees and replace it. This places pin 10 of the resistor pack into
pin 1 of the socket on the ICM-1900. Connections to the opto-isolated outputs do not
need to be modified.
This configuration can be specified when ordering the interconnect by using the
designation –INVOUT (ex. ICM-2900 –OPTO –INVOUT).
FROM
CONTROLLER
ICM-1900 / ICM-2900
CONNECTIONS
(-INVOUT OPTION)
ISO OUT POWER (ICM-1900,PIN 19)
OUT POWER (ICM-2900)
This point connected to
GND when resistor pack,
RP3, is inverted
10K OHMS
RP4 on ICM-1900
RP2 on ICM-2900
LOAD (OPTO-MODULE, ETC)
OUT[x] (66 - 73)
OUT[x] TTL
ISO POWER GND (ICM-1900,PIN 35)
OUT GND (ICM-2900)
Configuring for High Side Operation (-HISIDE option):
Galil can provide the opto-isolation configured for applications that require a High
Side Drive Circuit. This type of configuration is denoted as –HISIDE and must be
specified when the Interconnect Module is ordered.
In this configuration, the load is connected to ground and the output delivers current see diagram. With the –HISIDE configuration, the opto-isolated output can source
24mA of current and the maximum voltage to the load will be 1.5Volts less than the
voltage supplied to the circuit.
With the option –OPTO –HISIDE, the sense of the outputs will be inverted; when
the output is cleared (using the CB command), the output will source current to the
load and when the output is set (using the SB command), the output will not source
current to the load. To re-invert the sense of the outputs, use the option –OPTO –
HISIDE –INVOUT (see previous section “Inverting the Logic Sense of the OptoIsolation”).
-2Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com
FROM
CONTROLLER
+5V
ICM-1900 / ICM-2900
CONNECTIONS
(-HISIDE OPTION)
ISO POWER GND (ICM-1900,PIN 35)
OUT GND (ICM-2900)
TO BE CONNECTED TO USERS ISOLATED POWER SUPPLY
OUT[x] (66 - 73)
OUT[x] TTL
10K OHMS
RP4 on ICM-1900
RP2 on ICM-2900
TO LOAD (RELAY ETC.)
ISO OUT POWER (ICM-1900,PIN 19)
OUT POWER (ICM-2900)
TO BE CONNECTED TO USERS ISOLATED GND
NOTE: When the opto-isolation is configured for high side operation, the terminal
connections ISO GND and ISO POWER are not connected in the usual manner: The
ISO GND terminal should be connected to the opto-isolation power supply. The ISO
POWER terminal should be connected to the opto-isolated ground. The outputs
(OUT[1] through OUT[8] will be connected to the load).
-3Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com