The 61C540 is an Analog 16-Point Input Module made by Reliance Electric. This module was also probably made by Asea Brown Boveri and Baldor Reliance depending on when it was actually in production.
The 61C540 is a 4-20 MADC Analog Input Module that was created for an AutoMate system. This module has analog inputs that are wired directly onto a termination panel that comes separately from this module. The termination panel helps to facilitate communication between this module and a Multibus input module. This card has a few basic features. It has a broken wire detector, a square root extraction, an automatic calibration, and it can have 4 alarm set points per channel. It can also be scaled or unscaled.
The 61C540 has a simple faceplate that has only two features on it. It has a green LED indicator labeled OK and an RS-232 female connection that is labeled CHAN 0-15. An RS-232 connector cable can be attached to this port and then run to a terminal panel where it is attached to inputs. This cable normally comes with the termination panel that is sold separately from this module. The cable is 5ft in length.
The 61C540 has the capability to be placed on either a remote or local card storage rack. When this module is put on a rack, it can plug directly into the backplane of the rack. It uses two female card slots to do this. After you have plugged it in, you can then further secure it to the rack using mounting screws.