GE Industrial Solutions Entellisys 5.0 Integrator's Guide - Manual (Page 9)

PLC Inputs 9
Bit order
All 256 PLC inputs are stored in 16, 2 byte unsigned integer registers. The bit information is
stored in the 2-byte register in little-endian format. I.e. PLC input 1 = least significant bit.
Table 1-3, lists several examples to demonstrate how the bits are packed into each register.
Table 1-3 PLC Input examples
Example:
A 3rd party Modbus TCP client needs to be programmed to turn on PLC 23 which will, in turn, be
programmed in FlexLogic to operate a breaker.
1. Determine which register PLC Input#23 resides: 2nd register, 7th bit. 23-16=7.
2. Read DC01. Returns 32773
3. There are several other inputs that are configured, so a mask must be applied to manipulate
just PLC input 23
Original value: 1000 0000 0000 0101 (32773)
Apply Mask
To turn on PLC input 23, use the OR operation: OR 0000 0000 0100 0000 (64)
To turn off PLC input 23, use the AND operation: AND 1111 1111 1011 1111 (65471)
Write the result: 1000 0000 0100 0101 (32837)
4. Write 32837 to register DC01
Events:
If the “Events” parameter for the PLC Input is enabled, an event will be logged in the Events
screen when the state has changed. 'x' in the text of event is a placeholder for number from
range 1 to 256. Source of the events reports the CPU affected.
“PLC Input x On” - logged when PLC Input transitioned from low to high state.
“PLC Input x Off” - logged when PLC Input transitioned from high to low state.
PLC Inputs On Registers Values Binary
1 and 3 DC00 5 0000 0000 0000 0101
1, 3 and 16 DC00 32773 1000 0000 0000 0101
1, 3 and 20 DC00, DC00+1 5, 8 0000 0000 0000 0101 / 0000 0000 0000 1000