User`s guide

Page 43

Controlinc 1746-C (Version 5.21) Network Master Users Guide (2004-11-18)

Word [6]: FUNCTION: Poll for Accumulator (Totalizer) Data

This is a flag that indicates whether or not the 1746-C should request accumulator (totalizer)

data from the actuators when scanning. The totalizer values are stored in tables [9 & 10].

This data is retrieved with a separate Modbus read command when the particular actuator is

being polled (scanned).

If word [6] == 0 do not poll for totalizer data.

If word [6] =/= 0 (any non-zero value) … poll for totalizer data.

By default, word [6] == 0 … do not poll for totalizer data.

Word [7]: Additional Valves to Poll in the scan time-slice.

The process scheduler has 2 primary processes to monitor:

1. Scanning the network (polling valves)

2. PLC communication & service.

Each process is given a particular time slice to operate in/with.

By program architecture, it is guaranteed that after servicing a PLC request, one valve (the next

on the network after the previous one polled) will be polled for data. The number in word [7]

allows the operator to allocate additional valves to be polled before servicing the PLC again.

The larger this number is, the shorter the network scan time but the fewer interactions with the

PLC. The lower the number, the more service given to the PLC (for control and feedback) but

the slower the network scan time (because we are servicing the PLC commands to read/write

tables).

This number should be adjusted for the most optimal fit for the application.

The default value is 2.

The minimum value is zero (0).

The maximum value is the lesser of

• 9

• 1 less than the number of valves on the network.

Word [8]: Additional Message Response Delay

Word [8] offers the operator the chance to enter a desired ADDITIONAL expected delay when

receiving messages from the network. The value is in 10 ms increments and can have a range

of 0-30 (0 – 300 ms).

The default value is 0.