ONICON System-10 MODBUS - Manual (Page 8)

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System-10-MOD Network Interface Installation Guide 05/14 - 0653-10 / 18321
Page 8
1.4.3 Optional Network Interface With Isolated Digital Pulse Input (Di3)
The System-10 BTU Meter can be provided with an auxiliary pulse input for totalizing
pulse outputs from external devices such as water or gas meters. Pulses are accumulated
in an internal register, and the totalized value is available on the network. This register
can be zeroed via the network. The maximum register total is 9,999,999. The register will
rollover to zero when this value is exceeded.
If the auxiliary pulse input option was ordered at the same time the BTU Meter was
ordered, it will arrive fully configured and ready to use. If it was ordered after the BTU
Meter was delivered and is being installed as a field upgrade, it may be necessary to
configure the pulse input. The information required to configure the input is provided
below and on the following pages:
The input pulse must meet the following criteria:
1.
Frequency input range, 50 Hz maximum
2. 10 millisecond minimum pulse duration
Input Pulse Definition:
In order to configure the communications card auxiliary pulse input, you must first
determine which type of pulse your meter produces. The allowable types of input
pulses are described on the following pages. Based on the type of pulse, set the selector
switch (S1) on the communications circuit board (Fig. 1) to the correct setting.
Fig. 1
120 ohm Jumper Selectable
Termination Resistor
Pulse Type Selector Switch (S1)
Input Impedance Jumper (J1)
Aux Pulse Input (Di3) Connector (T2)
RS485 Connector (T1)
NOTE: MODBUS RS485 shown above. See appendix A-4 for MODBUS TCP/IP auxiliary input board.