Appendix G - Communications Gateway Module Installation Kit
106
3A2797ZAA
To get, receive or read data from the HFR/
NVH system, the controlling PLC needs to:
1. Write to the data exchange interface – data pointer
command location on the map (output bytes 20 –
21, O160 – O175) a value corresponding to the data
the PLC wants to receive.
2. Wait for the HFR to provide the same data
exchangeinterface - Pointer Last Serviced “
number written in the previous step at input byte
locations 26 – 27 (I208 – I223).
3. Read the requested data at input byte locations 28
– 31 (I224 – I255), data exchange interface – input
data element
To write or transmit data to the HFR
system, the controlling PLC needs to:
1. Write the data for the HFR system to data
exchange interface – output data element location,
output byte locations 22 – 25 (O176 – O207).
2. Write to the data exchange interface – data pointer
command location on the map (output bytes 20 –
21, O160 – O175) a value corresponding to the data
the PLC wants to transmit to the HFR.
3. The HFR will echo back to the PLC the data pointer
and the data element after the HFR system
processes the data transmit request to input
locations 26 – 27 (I208 – I223), and input locations
28 – 31 (I224 – I255) respectively.
NOTE:
When changes are made over the data
exchange interface, the HFR/ NVH system display
screen may not update immediately. It may be
necessary to navigate away from the screen then back
to it, or a new dispense may need to be triggered.
NOTE:
All Read designations on the Data Exchange are
assigned and Even numbers, whereas all Write
designations are assigned an Odd number
assignments.
