AP500/AP520/AP521 ACROPACK
USER
’S MANUAL
Acromag, Inc. Tel: 248-295-0310
- 17 - http://www.acromag.com
- 17 -
www.acromag.com
2.5 RS-422/485 Termination (AP521 Only)
The standard AP521 modules have 120ohm termination resistors installed
on both line drivers and receivers, as well as 560ohm biasing resistors
installed on the line drivers. For modules without termination please consult
the factory.
2.6 Noise and Grounding Considerations
The board is non-isolated, since there is electrical continuity between the
logic and field I/O grounds. As such, the field I/O connections are not
isolated from the system. Care should be taken in designing installations
without isolation to avoid noise pickup and ground loops caused by multiple
ground connections.
2.7 Logic Interface Connector
The AP module logic edge connector interfaces to the mating connector on
the carrier board. The pin assignments of this connector are standard for all
AP modules according to the PCI Express MINI Card Electromechanical
Specification, REV 1.2 (with exceptions shown in
Table 2.2
and noted
below).
Threaded metric M2.5 screws and spacers are supplied with the AP module
to provide additional stability for harsh environments (see Drawing XXX for
assembly details).
