NDTRELAY2
Installation Guide
Introduction
The NDTRELAY2 is an RS-232 relay interface that features: 8 Normally Open Contact Outputs, 4 Digital Inputs, and
16-Bit Contact or TTL Input Event Counters.
The NDTRELAY2 communicates via a standard RS-232 Port, using a three-wire interface. The signals used are
Received Data (RC), Transmitted Data (TX), and Ground (GND).
When added to an IOtech Non-Destructive Test system (NDT), or to an IOtech Temporary Online Monitoring and
Analysis system (TOMAS), the NDTRELAY2 allows the associated software (eZ-NDT or eZ-TOMAS) to read external
discrete signals and open and close relays relative to specified software events. The software controls all functions of the
NDTRELAY2. No user programming or setup is required. Refer to your eZ-NDT or eZ-TOMAS documentation for
instructions on how to perform NDTRELAY2 I/O operations.
NDTRELAY2, Input and Relay Connectors
Connecting the Communication Cable
WARNING
WARNING
WARNINGWARNING
Always turn OFF the NDTRELAY2 and unplug it before making or breaking any connections; or
before opening the unit for any reason. Failure to do so could result in electric shock, or equipment
damage.
With power to the NDTRELAY2 turned off (0), connect a null-modem cable to the unit’s DB9S connector. The
connector is labeled “RS-232 From PC.” Connect the other end of the null-modem cable to the host PC’s COM Port.
Note that IOtech’s PC/AT/XT null-modem serial cable, p/n CA-47, makes a good communication cable.
DB9S - Connects to the PC’s COM Port via a null-
NDTRELAY2, Power and Communication Connectors
NDTRELAY2, Installation Guide
modem cable, such as IOtech’s p/n CA-47.
p/n
958596
1099-0901
rev.
2.0
Connecting Digital Inputs and Relay Outputs
WARNING
WARNING
WARNINGWARNING
Always turn OFF the NDTRELAY2 and unplug it before making or breaking any connections; or before
opening the unit for any reason. Failure to do so could result in electric shock, or equipment damage.
Digital Connections Relay Output Connections
The four Digital Inputs have built-in weak pull-up resistors to
allow direct connection of dry contact inputs. These inputs
can be from any source, including switches and relays. TTL
signal sources [including TTL or NPN type proximity sensors]
can also be directly connected to Digital Input connections 0,
1, 2, or 3.
NDTRELAY2 has eight normally open relay outputs labeled 0
through 7. The relays are capable of switching AC or DC loads,
as follows: up to 1 amp at 30 VDC; up to 0.5 amp at 120 VAC.
A typical connection, for Relay 0, is represented in the
following figure.
A typical Digital Input connection setup is represented by the
following figure. Notice that the contacts (switches) for
channels 0, 1, and 2 share a common ground. The digital TTL
input is not connected to ground.
A Typical Setup for Digital Input
Typical Connection Shown for Relay 0
Event Counter Connections
The Event Counter can be configured to accept TTL or dry Contact Inputs. Connections for each are represented by the
following figures. Events are counted on the rising edge of the input, at which point the TTL signal switches from low to
high, or the dry contact opens.
Connecting a Contact Type Input
Dry Contact Type inputs must be connected between Ground
and the ECA Input connection.
* For dry Contact Type inputs, debounce capacitor C7 must be
installed on the Relay Board. See the following figure for
location. By default, C7 is installed when the NDTRELAY2
is shipped.
2
1099-0901,
p/n
2.0
rev
Connecting a TTL Type Input
TTL Type inputs are connected directly to the ECA contact.
** For TTL Type inputs, debounce capacitor C7 must be
removed. See the following figure for location.
958596
NDTRELAY2, Installation Guide
Supplying Power to NDTRELAY2
To supply power to the NDTRELAY2, plug the AC power cord into the unit’s Line Voltage Receptacle (see following
figure, lower image). Plug the other end of the cable into a suitable AC power outlet. Acceptable power is that which is in
the range of 85 VAC to 265 VAC, at 47 Hz to 440 Hz.
NDTRELAY2’s internal power supply converts the line voltage to +12 VDC. The DC power is made available to external
components through the DIN5 Power Out connector, located next to the Power Switch. You can power a ZonicBook from
this connector via a CA-115, DIN5 male to DIN5 male Power Cable. Note that an LED, located next to the Power Switch,
will light when the NDTRELAY2 is powered On (see following figure, lower image).
Capacitor C7 and Fuse Locations
WARNING
WARNING
WARNINGWARNING
Always turn OFF the NDTRELAY2 and unplug it before making or breaking any connections; or
before opening the unit for any reason. Failure to do so could result in electric shock, or equipment
damage.
RELAY CARD
Capacitor C7
0.1 µf
(Note 1)
Fuse, 3 Amp Line Voltage Receptacle DB9S (Connects DIN5 Power Switch
to PC COM Port) (VDC Out)
POWER
SUPPLY
PS-45-12
Power LED
Note 1: For dry Contact Type inputs, debounce capacitor C7 must be installed on the Relay Board. For TTL Type
inputs, C7 must be removed. Refer to Event Counter Connections, on page 2 of this document, for connection
drawings.
NDTRELAY2, Installation Guide
3
958596
Specifications
Contact Outputs
Quantity 8
Type SPST, Normally Open
AC Rating 0.5 Amp @ 120 VAC Max.
DC Rating 1.0 Amp @ 30 VDC Max.
Approvals UL, CSA
Mechanical Life 5 Million Operations, Minimum
Electrical Life 100,000 Operations, Minimum at full-load
Digital Inputs
Quantity 4
Type TTL or Contact (weak pull-up)
Input Voltage High 4.00 V, Minimum
Input Voltage Low 0.8 V, Maximum
Event Counter
Quantity 1
Type TTL or Contact
Resolution 16 Bits
Communication Interface
RS232 Standard DB9S (Female)
Configuration 9600 Baud, 8-Bit Words, No Parity, 1 Start Bit
Power
Line Voltage, Input 85 to 265 VAC, 47 to 440 Hz
DC Power Out + 12 VDC @ 3.5 A max., via DIN 5 Power Connector
Operating Environment
Temperature 0 to 50°C
Humidity 0 to 95% RH, non-condensing
4
1099-0901,
p/n
2.0
rev
958596
NDTRELAY2, Installation Guide
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