User`s guide
Copyright © 2004 EIM COMPANY, INC. • 13840 PIKE ROAD • MISSOURI CITY, TX. 77489
Page 93
Controlinc 1746-C (Version 5.21) Network Master Users Guide (2004-11-18)
6.2.2. Detailed Description of 1746-C Operation
1. Power up and self-initialization … LED1 & LED2 both on.
2. Perform the initial diagnostic scan to determine which actuators are actually on the network.
3. Turn LED1 & LED2 off.
4. Stay in a loop performing the following activities:
I. Setup to start new scan of network.
• If diagnostic scan:
- Ensure the communication ports are setup correctly.
- The previous scan period (group of scans) has finished.
- Toggle the preferred communication port.
• Toggle the state of LED1 … on or off.
II. Perform the Network Scan: Using a time-slice time sharing methodology, loop through all the
actuators on the network (starting from #1 and going through #n [the highest number on the
network]) such that:
--- (the valve scan time-slice) -----------
a. If a diagnostic scan …
- Clear any communication failure indications for the particular valve to be polled.
- Get system type ID … try on both ports.
- If an EIM system, get the firmware version ID.
b. If supposed to get totalizer data for the valve, do it.
c. If supposed to request a specific holding register, do it. If supposed to request a block of
holding registers from this actuator, do it.
d. If supposed to monitor or control the discrete user relay outputs on this actuator, do it.
e. If supposed to get TEC2000 input data, do it.
f. Get the rest of the “standard data” from the valve.
Note: If the 1746-C can’t communicate with this particular actuator that is supposed to be
on-line, it marks that actuator as “off-line” … to skip on the next scan cycle. If there are
problems communicating on any particular channel to the actuator, this is also recorded.
--- (the PLC interface time-slice) -----------
g. If ready to interface with the PLC (ready for the PLC time-slice) then do it. When
finished with this PLC interface time-slice, if the number of valves changed in table [0],
end this loop, reset the rest of the tables and setup to enter a diagnostic scan … restart
with new data.
Otherwise still in the valve scan time-slice … If not at the last valve on the network, loop
back (to step “a” above) and get data from the next actuator.
III. Network Scan cleanup
• Label Non-Used Actuator Operation. Mark all “non-used” actuator entries in the tables with
an invalid value (“-99”).
• Determine if the network is “down” by counting the number of actuators that did not
communicate with the 1746-C.
If the network is down, then turn LED2 on and force the next scan to be a diagnostic scan.
Otherwise ensure LED2 is off.
• Account for network scan timings to be displayed in table [0].
IV. Loop back to the top and start another network scan.