Rockwell Automation T812X Trusted Processor Interface Adaptor - Manual (Page 13)

Trusted
TM
Process Interface Adaptor T812X
Issue 8 Sep 07 PD-T812X 13
3. Input Configuration
3.1. Serial Ports
The serial ports connectors are arranged so that multi-drop RS422/485 connections can be easily
configured. J7, J8 and J10 together with LK1, LK2 and LK3 form the basic terminations for ports 1, 2
and 3 respectively.
For a single point connection the termination would be made to the relevant connector and its
corresponding link would be fitted. For a multi-drop connection the ‘incoming’ connections would be
made to the connections listed above and the ‘outgoing’ to J12, J9 or J11 for ports 1 to 3 respectively.
This time however, the link will be removed as only the last connection on a multipdrop chain should be
terminated.
The provision of the two connectors for each serial port will enable quicker configuration of serial
cabling as there is now no need to terminate two cables onto the same connector. The links LK1 to
LK3 provide the serial ports with an easy way to add 120 ohm AC termination onto the receivers
extremely close to the receiving devices.
The 4 wire serial ports 2 and 3 have connectors that are pin compatible with those used on the
Trusted
TM Communications Interface Termination Unit (T8153).
Serial connections should use screened twisted pair cable with the A-B signals connected as a pair.
The screen should be connected to chassis ground at one end only. Some equipment may require a
common 0V connection. In order to operate correctly, the 0V on the connector should be connected to
0V on the other equipment to facilitate this.
Further information on serial port configuration can be found in the standards listed below:
EIA/TIA-422-B
EIA-485
CCITT V.11
3.2. IRIG-B Ports
The IRIG-B002 input is a pulse width modulated signal ant 100bits/s and uses RS422 voltage levels.
Connection to this port should be by twisted pair cable. A 120 ohm termination (R13) is permanently
provided on the module. For multi-drop IRIG configurations, the resistor must be removed on all but
the last interface adaptor.
The IRIG-B122 input is a 1 KHz amplitude modulated signal where the modulating signal has the same
format as IRIG-B002. The peak amplitude (mark) of the input signal is nominally 1V to 6V into 600R.
The Trusted
TM TMR Processor is able to receive signal in the range 0.25V PK-PK to 10V PK-PK. IRIG-
B122 is normally provide via co-axial cable although any suitable medium would be acceptable.
Further information on IRIG configuration can be found in the standards listed below:
Range Commanders Council IRIG STANDARD 200-98
IEEE Std 1344-1995 Annex F.2