Micromod Micro-DCI: 53MC5000 Multi-Loop Process Controller Instruction Manual - Manual (Page 336)

APPENDIX A.0 DISCRETE OUTPUTS (DOs)
The tolerance ratings for the DO output switches are provided in the specifications table of Section
1 (Table 1-1). The maximum open voltage is 30 V dc and the maximum closed current is 50 mA
dc. A DO will operate any external device that can be made to switch if it does not require more
than 50 mA of current to the (+) terminal. Typical uses for a DO are to actuate a small relay, acti-
vate an external alarm buzzer, provide Contact Input (DI) to another controller, or provide output to
an operator panel.
A.1 DO EQUIVALENT CIRCUIT DESCRIPTION
The discrete output DOs are solid state devices analogous to single pole, single throw switches
with one terminal connected to power common. An equivalent simplified circuit for a DO is illus-
trated in Figure A-1; it is equivalent to an unpowered switch.
In Figure A-1, the switch is closed when the output logic bit (L24 for DO0, L25 for DO1) is set to 1,
provided that its respective invert bit (L288 for DO0, L289 for DO1) is 0. If the invert bit is set to 1,
the output bit will cause the switch to open when it is set to 1.
Figure A-1. DO Circuit and its Equivalent
Appendix A. Discrete Output DOs
A-1