ICP DAS USA GPS-721-MRTU User manual

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA 90717 1
GPS-721-MRTU
GPS Receiver and 1 DO, 1 PPS Output
Module
Quick Start Guide
This manual introduces the user to the methods used to implement the GPS-721-MRTU
module into their applications in a quick and easy way, and will only provide basic
instructions. For more detailed information, please refer to the GPS-721-MRTU user
manual located on the ICP DAS CD-ROM, or download it from the ICP DAS web site:
https://www.icpdas-usa.com/gps_721_mrtu.html
1. Pin Assignments and LED Indicators
Pin Assignments
GPS-721-MRTU

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA 90717 2
LED Indicators
LED
Status
Description
Sys.
ON
The module is operating/functioning correctly
OFF
The module has encountered an error
DO1
ON
Digital Output is active
OFF
Digital Output is inactive
S1
ON
Fewer than 5 signals received from GPS satellites.
OFF
Module is unable to receive sufficient GPS signals
ON
The number of signals received from GPS satellites is 5
S2
to 8
OFF
The number of signals received from GPS satellites is
less than 5
ON
The number of signals received from GPS satellites is
S3
more than 8
OFF
The number of signals received from GPS satellites is
less than 8
1 PPS
ON
The PPS signal is active
OFF
The PPS signal is inactive

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA
90717 3
2. Operation Modes
The back panel of the GPS-721-
MRTU contains the frame ground
and the INIT/Normal Switch. The
module has two operation modes
(INIT and Normal modes), which
can be determined via the switch
mechanism on the chassis. The
description and figure are as
follows.
Mode
Description
After setting the module to “INIT” mode and restarting the
module, a connection can be established using the default
module address and communication settings, allowing
new parameters for the module to be set.
INIT Mode:
INIT
Protocol: DCON
Module Address: 00
Communication Baud Rate: 9600bps
Checksum: Disabled
Note: The DCON command to set the address, the Baud
Rate and the checksum is %AANNTTCCFF. Refer to
section 2.1 for details.
Normal
In Normal mode, the module will operate based on the
user’s settings.

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA
90717 4
3. Wiring
Digital Output Wiring
PPS Wiring

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA
90717 5
Mounting
The GPS-721-MRTU can be mounted on either a DIN-Rail or a wall, or it
can be piggybacked to other modules using the bottom of the chassis.
DIN-Rail Mounting
The GPS-721-MRTU includes simple rail clips that allow for for reliable
mounting on a standard 35 mm DIN rail.
Three new DIN-Rail models are available, and each is made of stainless
steel, which is stronger than those made of aluminum. There is a screw
at one end, and a ring terminal is included so that it can be easily
connected to the earth ground.
Note: It is recommended that a 16 –14 AWG wire is used to connect the DIN
rail to the earth ground.

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA
90717 6
Piggyback Mounting
The GPS-721-MRTU has two holes on either side of the module to enable
piggyback mounting. Refer to the figure below for an illustration of how to
piggyback the modules.

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA
90717 7
4. Using the Module
This section describes the installation of the GPS-721-MRTU, and provides
details of how to begin using the module.
1. Refer to Section 1 for details of the pin assignments.
2. Connect the module to the RS-485 network using the DATA+ and DATA-
pins. See Section 1 for details of the pin assignments. If the Host is only
equipped with an RS-232 interface, then an RS-232 to RS-485 converter
will be required. The GPS-721-MRTU supports RS-232 connections.
Refer to the “I-7000 Bus Converter User Manual” for more information.

GPS-721-MRTU GPS Receiver - QuickStart (Jan/2019)
ICP DAS USA, Inc. | www.icpdas-usa.com | 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita, CA
90717 8
Default address and communication parameters:
Protocol: Modbus RTU
Module address: 01
Communication Baud Rate: 9600 bps
Configure the module by sending the %AANNTTCCFF command. See
Section 2.1 of the “GPS-721-MRTU User Manual” for details.
ICP DAS provides two free tools that allow the GPS-721-MRTU to be
easily configured, the DCON Utility and the Send232 application, both of
which can be downloaded from
http://ftp.icpdas.com/pub/cd/8000cd/napdos/driver/dcon_utility/
3. All module functions can be implemented using the DCON commands
described in Section 2.
4. If the Host is a PC with a Windows operating system installed, the DCON
Utility can be used to allow easy configuration and reading of data. The
DCON Utility can be downloaded from the ICP DAS website
(http://www.icpdas.com), and documentation for the DCON Utility can be
found in the ”Getting Started For I-7000 Series Modules” manual.
Note 1: The DCON Utility is provided to enable commands to be sent to the
GPS-721-MRTU. The graphic settings of the GPS-721-MRTU are
not supported by the DCON Utility.
Note 2: If GPS-721-MRTU is unable to receive a GPS signal, check the
position of the antenna and if the problem persists, try relocating the
GPS antenna outside.