National Instruments 8-Channel Solid-State Relay (SSR) Digital Output NI... User manual

OPERATING INSTRUCTIONS
NI 9485
8-Channel Solid-State Relay (SSR) Digital Output
Module

NI 9485 Operating Instructions 2 ni.com
These operating instructions describe how to use the National
Instruments 9485. For information about installing, configuring,
and programming the system, refer to the system documentation.
Visit ni.com/info and enter the info code rdsoftwareversion
to determine which software you need for the modules you are
using.
Note The safety guidelines and specifications in this
document are specific to the NI 9485. The other
components in the system might not meet the same safety
ratings and specifications. Refer to the documentation for
each component in the system to determine the safety
ratings and specifications for the entire system.
Safety Guidelines
Operate the NI 9485 only as described in these operating
instructions.
Hot Surface This icon denotes that the component may be
hot. Touching this component may result in bodily injury.

© National Instruments Corp. 3 NI 9485 Operating Instructions
Safety Guidelines for Hazardous Voltages
If hazardous voltages are connected to the module, take the
following precautions. A hazardous voltage is a voltage greater
than 42.4 Vpk or 60 VDC to earth ground.
Caution Ensure that hazardous voltage wiring is
performed only by qualified personnel adhering to local
electrical standards.
Caution Do not mix hazardous voltage circuits and
human-accessible circuits on the same module.
Caution When module terminals are hazardous voltage
LIVE (>42.4Vpk/60 VDC), you must ensure that devices
and circuits connected to the module are properly
insulated from human contact. You must use the NI 9939
connector backshell kit to ensure that the terminals are
not accessible.

NI 9485 Operating Instructions 4 ni.com
Figure 1 shows the NI 9939 connector backshell.
Figure 1. NI 9939 Connector Backshell
Safety Guidelines for Hazardous Locations
The NI 9485 is suitable for use in Class I, Division 2, Groups A, B,
C, D, T4 hazardous locations; Class I, Zone 2, AEx nA II T4 and
Ex nA II T4 hazardous locations; and nonhazardous locations only.
Follow these guidelines if you are installing the NI 9485 in a
potentially explosive environment. Not following these guidelines
may result in serious injury or death.

© National Instruments Corp. 5 NI 9485 Operating Instructions
Caution Do not disconnect I/O-side wires or connectors
unless power has been switched off or the area is known
to be nonhazardous.
Caution Do not remove modules unless power has been
switched off or the area is known to be nonhazardous.
Caution Substitution of components may impair
suitability for Class I, Division 2.
Caution For Zone 2 applications, install the system in an
enclosure rated to at least IP 54 as defined by IEC 60529
and EN 60529.
Caution For Zone 2 applications, install a protection
device across the positive and negative terminals of the
external power supply (or supplies). The device must
prevent the external power supply from exceeding
80 V if there is a transient overvoltage condition.

NI 9485 Operating Instructions 6 ni.com
Special Conditions for Hazardous Locations Use in Europe
This equipment has been evaluated as EEx nA II T4 equipment
under DEMKO Certificate No. 03 ATEX 0324020X. The
equipment is marked II 3G and is suitable for use in
Zone 2 hazardous locations.
Wiring the NI 9485
The NI 9485 has a 16-terminal, detachable screw-terminal
connector that provides connections for eight solid-state relay
channels. Each channel has two interchangeable terminals, CHa
and CHb. Refer to Table 1 for the terminal assignments for each
channel.

© National Instruments Corp. 7 NI 9485 Operating Instructions
Table 1. Terminal Assignments
Module Ter mi nal Signal
0CH0a
1CH0b
2CH1a
3CH1b
4CH2a
5CH2b
6CH3a
7CH3b
8CH4a
9CH4b
10 CH5a
11 CH5b
12 CH6a
13 CH6b
14 CH7a
15 CH7b
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

NI 9485 Operating Instructions 8 ni.com
Wiring for High-Vibration Applications
If an application is subject to high vibration, National Instruments
recommends that you either use ferrules to terminate wires to the
detachable screw-terminal connector or use the NI 9939 backshell
kit to protect the connections. Refer to Figure 2 for an illustration.
Figure 2. 16-Pin Detachable Screw Terminal with Ferrule
Ferrule

© National Instruments Corp. 9 NI 9485 Operating Instructions
Connecting Loads to the NI 9485
You can connect loads to the NI 9485. Connect the load to one of
the leads of the power source. Connect either the CHa or the CHb
terminal to the load and the other terminal to the other lead of the
AC or DC power source. Figure 3 shows a possible configuration
where the load is connected to the CHb terminal and the DC or AC
power source.
Figure 3. Connecting a Load to the NI 9485
NI 9485
+
–
Load
or
AC
CHa
CHb

NI 9485 Operating Instructions 10 ni.com
When you write an ON command to a channel, the SSR is closed
and the terminal that is connected to the load allows current to flow
or allows voltage to be applied to the load. When you write an OFF
command to a channel, the switch opens, disconnecting the circuit
so no current flows and no voltage is applied to the load.
Protecting Inductive Loads
When inductive loads are connected to the NI 9485 relay outputs,
a large counter-electromotive force may occur at switching time
because of the energy stored in the inductive load. These flyback
voltages can damage the relay outputs and/or the external power
supply.
Limit flyback voltages at your inductive load by installing one of
the following:
• For DC loads—Install a flyback diode within 18 in. of the load.
• For AC loads—Install a metal oxide varistor (MOV) rated for
30 Vrms or slightly higher.