Rs-485 Communications Connections - Ametek Thermox 2000 ATEX Series User Manual

3-38 | Thermox Series 2000 WDG-HPII / HPIIC - ATEX
Combustibles remote calibration unit connections
If you have the combustibles option (and a combustibles RCU) you must
also make the following connection (see Figure 3-21.)
SPAN2 - 17 on RCU
Digital input to initiate Remote Calibration Unit
The digital input connections on the wiring card allow you to initiate a
remote calibration from a location other than the control unit (see Figure
3-21). For this option to work, you must have a remote calibration unit and
an auto calibration card. The system monitors the digital input, and when
the switch closes, it sends the system into an automatic calibration. The
switch you connect to this digital input must be a normally open switch.
Digital input connections are labeled as follows on the wiring card:
DIGIN +
DIGIN -

RS-485 Communications Connections

The Series 2000 control unit has the ability to communicate with other
computers that use the same protocol and have the same hardware inter-
face. See the "Serial Communications" Appendix in the back of this manual
for information on the RS-485 serial communications protocol.
2-Wire connections
The connections used for RS-485 2-wire communications on the wiring
card are labeled as follows:
4WTX+/2W+
4WTX-/2W-
Connect all the 2-wire pluses (+) and all the 2-wire minuses (-) in parallel
with all the devices in a daisy chain fashion, including all the control units
on the network and the host computer. In addition, on the host computer
connect the receive and transmit terminal block connections (see
Figure 3-22). Be sure to use twisted-pair cable for all connections.