DDS EX
Explosion-Proof Transmitter and Controller Instruction Manual
77
Scanner Operation
The DSS EX Transmitter/Controller is capable of operating as a Modbus Master, Slave or Snooper. As a
Slave, the DSS EX requires connection to a Master device: PLC, DCS, etc. As a Master, the DSS EX
interfaces up to sixteen slave devices and can alternately display their Process Variables. As a Snooper it
can be connected anywhere in the RS-485 bus to read any of the variables being requested by the Master
device.
Four math channels (C1-C4) are available to perform operations on any PV or math channel, with adder
and factor constants, and display the results. Engineering units or tags may be displayed with all PVs or
math channels. Another level of Math functions can be performed on the resultant math channel Math2.
For example, the operator can use the Math2 Channel to calculate the Sum of all other Math Channels,
which may have each performed a different Math function.
The dual-line display can be customized by the user. Typically, the upper display is used to display the PV,
while the lower display is used to display the tag for each PV.
Additionally, the scanner can be set up to display any input or math channel on the upper display and
alternate between tag & units on the lower display. The relays and analog output can be programmed to
operate based on any PV or math channel.
The scanner is capable of accepting two analog input channels (A and B) of either current (0-20 mA,
4-20 mA) or voltage signals (0-5 V, 1-5 V, 0-10 V,
±
10 V) and displaying these signals in engineering units
from -99999 to 999999 (
e.g.
a 4-20 mA signal could be displayed as -50.000 to 50.000). The analog input
channels must be mapped to PVs using the IDs 256-259.
Front Panel Buttons Operation
Button Symbol
Description
Press to enter, exit Programming Mode,
or exit max/min readings
Press to move to the previous PV or
math channel
Press to move to the next PV or math
channel
Press once to pause scanning, press
again to resume scanning
