Rogue Engineering 1950-251 - Manual (Page 2)

Charging Ahead
Rogue Engineering Inc.
3860 S. Jason Street
Englewood Colorado 80110
1-800-364-0659 (Toll Free) 1-303-734-0706 (Phone)
1-303-734-0517 (Fax) www.rogue-engr.com
[email protected] or [email protected]
PORT FUNCTION PINS PIN DESCRIPTION
BATT Battery Connector
(6-30V)
- Negative battery terminal
+ Positive battery terminal
D-OUT* Digital Output (open collector,
optically isolated) Indicates
communication errors
- Negative digital output terminal
+ Positive digital output terminal
COM1 MODBUS Master 1 port
(9600bps, 1 start,8 data, No
parity,1 stop)
RX RS-232 Reception line
TX RS-232 Transmission line
GND Ground
LOI RX
(Do not Use)
Local Operator Interface reception line
LOI TX
(Do not Use)
Local Operator Interface transmission
line
COM2 MODBUS Master 2 port
(9600bps, 1 start,8 data, No
parity,1 stop)
RX RS-232 Reception line
TX RS-232 Transmission line
GND Ground
A RS-485 A line
B RS-485 B line
COM3 MODBUS Master 3 port
(9600bps, 1 start,8 data, No
parity,1 stop)
RX RS-232 Reception line
TX RS-232 Transmission line
GND Ground
A RS-485 A line
B RS-485 B line
COM4 MODBUS Slave port
(9600bps, 1 start,8 data, No
parity,1 stop)
RX RS-232 Reception line
TX RS-232 Transmission line
GND Ground
A RS-485 A line
B RS-485 B line
INTRODUCTION
The Modbus Gateway is a communication device that enables up to 3 Modbus
masters, two via RS-232 or RS-485 and one via RS-232, to communicate and
share a single Modbus slave device via RS-232 or RS-485.
SETUP - Wiring
QUICKSTART
1. Connect battery terminal as indicated on Wiring Diagram
2. Connect slave device on COM4 on the appropriate interface
3. Connect master devices on COM1-COM3 on the appropriate interface
ELECTRICAL / ENVIRONMENTAL SPECIFICATIONS
• Input Voltage (Bat+ to Bat-): 6V-30V
• Power Consumption: 85mW typical (7mA at 12V input)
• Ambient Temperature: -40 to 60 °C
• Pluggable Connectors: 12AWG max.
Time
master-gateway
= 10000 x (Character Count) (mS)
9600
The transmission time from the Modbus gateway to the device can be estimated using the
following formula:
Time
gateway-slave
= 10000 x (Character Count) (mS)
9600
The total transmission time from master to device can be estimated using the following
formula:
Time
master-slave
= 2 x Time
master-gateway
+ 2 x Time
gateway-slave
(mS)
OR
Time
master-slave
= 40000 x (Character Count) (mS)
9600
Finally, taking into account there is likelihood that there may be at least two messages
buffered from the other two masters, the minimum timeout period should be
Timeout
master
> 3 x Time
master-slave
(mS)
APPENDIX
Estimating Modbus Serial Message Timing
It is crucial to estimate the transmission time for Modbus messages in order
to set proper communication. For the Modbus Gateway settings (9600 baud,
1-8-N-1) the transmission time from a master to the Modbus Gateway can be
estimated using the following formula:
*Requires external pull-up resistor
Also, please note that the Modbus Gateway has incorporated a 4 second timeout while
waiting for a response from the slave device. This timeout should be taken into account
within the master timeout interval. If not taken into account it will result in the loss of
messages sent during the 4 second period.