
User's Guide ______________________________________________________________________
120 _________________________________________________________________ M210566EN-H
Example: Activate and then release all four relays.
>rtest on on on on
ON ON ON ON
>
>rtest off off off off
OFF OFF OFF OFF
>
Enter the command RTEST without parameters to stop testing.
Operation of the RS-485 Module
The RS-485 interface enables communication between RS-485 network
and HMT330 transmitter. The RS-485 interface is isolated and offers a
maximum communications rate of 115 200 bits/s. (For maximum bus
length of 1 km, use bit rate 19200 b/s or less.)
When selecting an RS-232-RS-485 converter for the network, avoid self
powered converters as they don't necessarily support the needed power
consumption.
Echo function shall be always disabled (OFF) when using the 2-wire
connection. When using the 4-wire connection you can disable/enable the
echo setting.
NOTE
User port on HMT330 main board cannot be used and connected when
RS-485 module is connected. Service port is operating normally.
Networking Commands
Set the RS-422/485 interface by using the following commands. The
other serial line commands are presented in section List of Serial
Commands on page 87.
RS-485 configuration commands SERI; ECHO; SMODE; INTV and
ADDR may be entered by using either the service port or RS-422/485
port. Also the optional display/keypad can be used, see section User Port
Serial Settings on page 98.
SDELAY
With the SDELAY command you can set delay (response time) for user
port (RS232 or RS485), or view currently set delay value. Value
corresponds to tens of milliseconds (eg. 5 = 0.050s minimum answer
delay). The value can be set between 0...254.
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