Transducer Inputs And Outputs - GE C30 Instruction Manual
Controller system
Hide thumbs
Also See for C30:
- Instruction manual (488 pages) ,
- Communications manual (532 pages) ,
- Instruction manual (480 pages)
Table of Contents
Advertisement
CHAPTER 3: INSTALLATION
WIRING
Figure 3-15: Current through contact inputs with auto-burnishing
3
Regular contact inputs limit current to less than 3 mA to reduce station battery burden. In contrast, contact inputs with
auto-burnishing allow currents up to 50 to 70 mA at the first instance when the change of state was sensed. Then, within
25 to 50 ms, this current is slowly reduced to 3 mA as indicated. The 50 to 70 mA peak current burns any film on the
contacts, allowing for proper sensing of state changes. If the external device contact is bouncing, the auto-burnishing
starts when external device contact bouncing is over.
Another important difference between the auto-burnishing input module and the regular input modules is that only two
contact inputs have common ground, as opposed to four contact inputs sharing one common ground (see the Contact
Input and Output Module Wiring diagrams). This is beneficial when connecting contact inputs to separate voltage sources.
Consequently, the threshold voltage setting is also defined per group of two contact inputs.
The auto-burnish feature can be disabled or enabled using the DIP switches found on each daughter card. There is a DIP
switch for each contact, for a total of 16 inputs.
Figure 3-16: Auto-burnish DIP switches
The auto-burnish circuitry has an internal fuse for safety purposes. During regular maintenance, check the auto-burnish
functionality using an oscilloscope.
3.3.6 Transducer inputs and outputs
Transducer input modules can receive input signals from external DCmA output transducers (DCmA In) or resistance
temperature detectors (RTDs). Hardware and software are provided to receive signals from these external transducers and
convert these signals into a digital format for use as required.
Transducer output modules provide DC current outputs in several standard DCmA ranges. Software is provided to
configure virtually any analog quantity used in the relay to drive the analog outputs.
C30 CONTROLLER SYSTEM – INSTRUCTION MANUAL
3-19
Advertisement
Table of Contents
